algebra.continued_fractions.computation.approximations ⟷ Mathlib.Algebra.ContinuedFractions.Computation.Approximations

mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Kappelmann
 -/
 import Algebra.ContinuedFractions.Computation.CorrectnessTerminating
-import Data.Nat.Fib
+import Data.Nat.Fib.Basic
 import Tactic.SolveByElim
 
 #align_import algebra.continued_fractions.computation.approximations from "leanprover-community/mathlib"@"cff8231f04dfa33fd8f2f45792eebd862ef30cad"
@@ -415,7 +415,7 @@ theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
       _ = (-1) ^ (n + 1) := by assumption
     suffices ppA * pB - ppB * pA = (-1) ^ n
       by
-      have pow_succ_n : (-1 : K) ^ (n + 1) = -1 * (-1) ^ n := pow_succ (-1) n
+      have pow_succ_n : (-1 : K) ^ (n + 1) = -1 * (-1) ^ n := pow_succ' (-1) n
       rw [pow_succ_n, ← this]
       ring
     exact IH <| Or.inr <| mt (terminated_stable <| n.sub_le 1) not_terminated_at_n

mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

@@ -181,7 +181,7 @@ theorem of_part_num_eq_one_and_exists_int_part_denom_eq {gp : GeneralizedContinu
     by
     have : (of v).s.get? n = some ⟨1, ifp.b⟩ :=
       nth_of_eq_some_of_succ_nth_int_fract_pair_stream stream_succ_nth_eq
-    have : some gp = some ⟨1, ifp.b⟩ := by rwa [nth_s_eq] at this 
+    have : some gp = some ⟨1, ifp.b⟩ := by rwa [nth_s_eq] at this
     injection this
   simp [this]
 #align generalized_continued_fraction.of_part_num_eq_one_and_exists_int_part_denom_eq GeneralizedContinuedFraction.of_part_num_eq_one_and_exists_int_part_denom_eq
@@ -195,7 +195,7 @@ theorem of_part_num_eq_one {a : K} (nth_part_num_eq : (of v).partialNumerators.g
   obtain ⟨gp, nth_s_eq, gp_a_eq_a_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.a = a;
   exact exists_s_a_of_part_num nth_part_num_eq
   have : gp.a = 1 := (of_part_num_eq_one_and_exists_int_part_denom_eq nth_s_eq).left
-  rwa [gp_a_eq_a_n] at this 
+  rwa [gp_a_eq_a_n] at this
 #align generalized_continued_fraction.of_part_num_eq_one GeneralizedContinuedFraction.of_part_num_eq_one
 -/
 
@@ -207,7 +207,7 @@ theorem exists_int_eq_of_part_denom {b : K}
   obtain ⟨gp, nth_s_eq, gp_b_eq_b_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.b = b;
   exact exists_s_b_of_part_denom nth_part_denom_eq
   have : ∃ z : ℤ, gp.b = (z : K) := (of_part_num_eq_one_and_exists_int_part_denom_eq nth_s_eq).right
-  rwa [gp_b_eq_b_n] at this 
+  rwa [gp_b_eq_b_n] at this
 #align generalized_continued_fraction.exists_int_eq_of_part_denom GeneralizedContinuedFraction.exists_int_eq_of_part_denom
 -/
 
@@ -260,7 +260,7 @@ theorem fib_le_of_continuantsAux_b :
         suffices : (fib (n + 1) : K) ≤ gp.b * pconts.b
         solve_by_elim [add_le_add ppred_nth_fib_le_ppconts_B]
         -- finally use the fact that 1 ≤ gp.b to solve the goal
-        suffices 1 * (fib (n + 1) : K) ≤ gp.b * pconts.b by rwa [one_mul] at this 
+        suffices 1 * (fib (n + 1) : K) ≤ gp.b * pconts.b by rwa [one_mul] at this
         have one_le_gp_b : (1 : K) ≤ gp.b :=
           of_one_le_nth_part_denom (part_denom_eq_s_b s_ppred_nth_eq)
         have : (0 : K) ≤ fib (n + 1) := by exact_mod_cast (fib (n + 1)).zero_le
@@ -349,10 +349,9 @@ theorem of_denom_mono : (of v).denominators n ≤ (of v).denominators (n + 1) :=
   by
   let g := of v
   cases' Decidable.em <| g.partial_denominators.terminated_at n with terminated not_terminated
-  · have : g.partial_denominators.nth n = none := by rwa [Stream'.Seq.TerminatedAt] at terminated 
+  · have : g.partial_denominators.nth n = none := by rwa [Stream'.Seq.TerminatedAt] at terminated
     have : g.terminated_at n :=
-      terminated_at_iff_part_denom_none.elim_right
-        (by rwa [Stream'.Seq.TerminatedAt] at terminated )
+      terminated_at_iff_part_denom_none.elim_right (by rwa [Stream'.Seq.TerminatedAt] at terminated)
     have : g.denominators (n + 1) = g.denominators n :=
       denominators_stable_of_terminated n.le_succ this
     rw [this]
@@ -524,7 +523,7 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
       have : 0 < ifp.fr⁻¹ := by
         suffices 0 < ifp.fr by rwa [inv_pos]
         have : 0 ≤ ifp.fr := int_fract_pair.nth_stream_fr_nonneg stream_nth_eq
-        change ifp.fr ≠ 0 at ifp_fr_ne_zero 
+        change ifp.fr ≠ 0 at ifp_fr_ne_zero
         exact lt_of_le_of_ne this ifp_fr_ne_zero.symm
       have : 0 < ifp.fr⁻¹ * B := mul_pos this zero_lt_B
       have : 0 < pB + ifp.fr⁻¹ * B := add_pos_of_nonneg_of_pos zero_le_pB this
@@ -578,8 +577,8 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
       by
       -- apply `sub_convergens_eq` and simplify the result
       have tmp := sub_convergents_eq stream_nth_eq
-      delta at tmp 
-      simp only [stream_nth_fr_ne_zero, conts_eq.symm, pred_conts_eq.symm] at tmp 
+      delta at tmp
+      simp only [stream_nth_fr_ne_zero, conts_eq.symm, pred_conts_eq.symm] at tmp
       rw [tmp]
       simp only [denom']
       ring_nf
@@ -589,7 +588,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
     by
     have : (fib (n + 2) : K) ≤ nextConts.b :=
       fib_le_of_continuants_aux_b (Or.inr not_terminated_at_n)
-    rwa [nextConts_b_eq] at this 
+    rwa [nextConts_b_eq] at this
   have conts_b_ineq : (fib (n + 1) : K) ≤ conts.b :=
     haveI : ¬g.terminated_at (n - 1) := mt (terminated_stable n.pred_le) not_terminated_at_n
     fib_le_of_continuants_aux_b <| Or.inr this
@@ -624,7 +623,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
       rwa [abs_of_pos this]
     rwa [this]
   suffices : 0 < denom ∧ denom ≤ denom';
-  exact div_le_div_of_le_left zero_le_one this.left this.right
+  exact div_le_div_of_nonneg_left zero_le_one this.left this.right
   constructor
   · have : 0 < pred_conts.b + gp.b * conts.b :=
       lt_of_lt_of_le

mathlib commit https://github.com/leanprover-community/mathlib/commit/ce64cd319bb6b3e82f31c2d38e79080d377be451

@@ -3,9 +3,9 @@ Copyright (c) 2020 Kevin Kappelmann. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Kappelmann
 -/
-import Mathbin.Algebra.ContinuedFractions.Computation.CorrectnessTerminating
-import Mathbin.Data.Nat.Fib
-import Mathbin.Tactic.SolveByElim
+import Algebra.ContinuedFractions.Computation.CorrectnessTerminating
+import Data.Nat.Fib
+import Tactic.SolveByElim
 
 #align_import algebra.continued_fractions.computation.approximations from "leanprover-community/mathlib"@"cff8231f04dfa33fd8f2f45792eebd862ef30cad"
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/8ea5598db6caeddde6cb734aa179cc2408dbd345

@@ -2,16 +2,13 @@
 Copyright (c) 2020 Kevin Kappelmann. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Kappelmann
-
-! This file was ported from Lean 3 source module algebra.continued_fractions.computation.approximations
-! leanprover-community/mathlib commit cff8231f04dfa33fd8f2f45792eebd862ef30cad
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Algebra.ContinuedFractions.Computation.CorrectnessTerminating
 import Mathbin.Data.Nat.Fib
 import Mathbin.Tactic.SolveByElim
 
+#align_import algebra.continued_fractions.computation.approximations from "leanprover-community/mathlib"@"cff8231f04dfa33fd8f2f45792eebd862ef30cad"
+
 /-!
 # Approximations for Continued Fraction Computations (`generalized_continued_fraction.of`)
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/2a0ce625dbb0ffbc7d1316597de0b25c1ec75303

@@ -70,6 +70,7 @@ of great interest for the end user.
 -/
 
 
+#print GeneralizedContinuedFraction.IntFractPair.nth_stream_fr_nonneg_lt_one /-
 /-- Shows that the fractional parts of the stream are in `[0,1)`. -/
 theorem nth_stream_fr_nonneg_lt_one {ifp_n : IntFractPair K}
     (nth_stream_eq : IntFractPair.stream v n = some ifp_n) : 0 ≤ ifp_n.fr ∧ ifp_n.fr < 1 :=
@@ -85,19 +86,25 @@ theorem nth_stream_fr_nonneg_lt_one {ifp_n : IntFractPair K}
     rw [← ifp_of_eq_ifp_n, int_fract_pair.of]
     exact ⟨fract_nonneg _, fract_lt_one _⟩
 #align generalized_continued_fraction.int_fract_pair.nth_stream_fr_nonneg_lt_one GeneralizedContinuedFraction.IntFractPair.nth_stream_fr_nonneg_lt_one
+-/
 
+#print GeneralizedContinuedFraction.IntFractPair.nth_stream_fr_nonneg /-
 /-- Shows that the fractional parts of the stream are nonnegative. -/
 theorem nth_stream_fr_nonneg {ifp_n : IntFractPair K}
     (nth_stream_eq : IntFractPair.stream v n = some ifp_n) : 0 ≤ ifp_n.fr :=
   (nth_stream_fr_nonneg_lt_one nth_stream_eq).left
 #align generalized_continued_fraction.int_fract_pair.nth_stream_fr_nonneg GeneralizedContinuedFraction.IntFractPair.nth_stream_fr_nonneg
+-/
 
+#print GeneralizedContinuedFraction.IntFractPair.nth_stream_fr_lt_one /-
 /-- Shows that the fractional parts of the stream are smaller than one. -/
 theorem nth_stream_fr_lt_one {ifp_n : IntFractPair K}
     (nth_stream_eq : IntFractPair.stream v n = some ifp_n) : ifp_n.fr < 1 :=
   (nth_stream_fr_nonneg_lt_one nth_stream_eq).right
 #align generalized_continued_fraction.int_fract_pair.nth_stream_fr_lt_one GeneralizedContinuedFraction.IntFractPair.nth_stream_fr_lt_one
+-/
 
+#print GeneralizedContinuedFraction.IntFractPair.one_le_succ_nth_stream_b /-
 /-- Shows that the integer parts of the stream are at least one. -/
 theorem one_le_succ_nth_stream_b {ifp_succ_n : IntFractPair K}
     (succ_nth_stream_eq : IntFractPair.stream v (n + 1) = some ifp_succ_n) : 1 ≤ ifp_succ_n.b :=
@@ -115,7 +122,9 @@ theorem one_le_succ_nth_stream_b {ifp_succ_n : IntFractPair K}
     apply one_le_inv h this
   simp only [le_of_lt (nth_stream_fr_lt_one nth_stream_eq)]
 #align generalized_continued_fraction.int_fract_pair.one_le_succ_nth_stream_b GeneralizedContinuedFraction.IntFractPair.one_le_succ_nth_stream_b
+-/
 
+#print GeneralizedContinuedFraction.IntFractPair.succ_nth_stream_b_le_nth_stream_fr_inv /-
 /--
 Shows that the `n + 1`th integer part `bₙ₊₁` of the stream is smaller or equal than the inverse of
 the `n`th fractional part `frₙ` of the stream.
@@ -136,6 +145,7 @@ theorem succ_nth_stream_b_le_nth_stream_fr_inv {ifp_n ifp_succ_n : IntFractPair
     rwa [← this]
   exact floor_le ifp_n.fr⁻¹
 #align generalized_continued_fraction.int_fract_pair.succ_nth_stream_b_le_nth_stream_fr_inv GeneralizedContinuedFraction.IntFractPair.succ_nth_stream_b_le_nth_stream_fr_inv
+-/
 
 end IntFractPair
 
@@ -145,6 +155,7 @@ fraction `generalized_continued_fraction.of`.
 -/
 
 
+#print GeneralizedContinuedFraction.of_one_le_get?_part_denom /-
 /-- Shows that the integer parts of the continued fraction are at least one. -/
 theorem of_one_le_get?_part_denom {b : K}
     (nth_part_denom_eq : (of v).partialDenominators.get? n = some b) : 1 ≤ b :=
@@ -157,7 +168,9 @@ theorem of_one_le_get?_part_denom {b : K}
   rw [← ifp_n_b_eq_gp_n_b]
   exact_mod_cast int_fract_pair.one_le_succ_nth_stream_b succ_nth_stream_eq
 #align generalized_continued_fraction.of_one_le_nth_part_denom GeneralizedContinuedFraction.of_one_le_get?_part_denom
+-/
 
+#print GeneralizedContinuedFraction.of_part_num_eq_one_and_exists_int_part_denom_eq /-
 /--
 Shows that the partial numerators `aᵢ` of the continued fraction are equal to one and the partial
 denominators `bᵢ` correspond to integers.
@@ -175,7 +188,9 @@ theorem of_part_num_eq_one_and_exists_int_part_denom_eq {gp : GeneralizedContinu
     injection this
   simp [this]
 #align generalized_continued_fraction.of_part_num_eq_one_and_exists_int_part_denom_eq GeneralizedContinuedFraction.of_part_num_eq_one_and_exists_int_part_denom_eq
+-/
 
+#print GeneralizedContinuedFraction.of_part_num_eq_one /-
 /-- Shows that the partial numerators `aᵢ` are equal to one. -/
 theorem of_part_num_eq_one {a : K} (nth_part_num_eq : (of v).partialNumerators.get? n = some a) :
     a = 1 :=
@@ -185,7 +200,9 @@ theorem of_part_num_eq_one {a : K} (nth_part_num_eq : (of v).partialNumerators.g
   have : gp.a = 1 := (of_part_num_eq_one_and_exists_int_part_denom_eq nth_s_eq).left
   rwa [gp_a_eq_a_n] at this 
 #align generalized_continued_fraction.of_part_num_eq_one GeneralizedContinuedFraction.of_part_num_eq_one
+-/
 
+#print GeneralizedContinuedFraction.exists_int_eq_of_part_denom /-
 /-- Shows that the partial denominators `bᵢ` correspond to an integer. -/
 theorem exists_int_eq_of_part_denom {b : K}
     (nth_part_denom_eq : (of v).partialDenominators.get? n = some b) : ∃ z : ℤ, b = (z : K) :=
@@ -195,6 +212,7 @@ theorem exists_int_eq_of_part_denom {b : K}
   have : ∃ z : ℤ, gp.b = (z : K) := (of_part_num_eq_one_and_exists_int_part_denom_eq nth_s_eq).right
   rwa [gp_b_eq_b_n] at this 
 #align generalized_continued_fraction.exists_int_eq_of_part_denom GeneralizedContinuedFraction.exists_int_eq_of_part_denom
+-/
 
 /-!
 One of our next goals is to show that `bₙ * Bₙ ≤ Bₙ₊₁`. For this, we first show that the partial
@@ -206,6 +224,7 @@ denominators `Bₙ` are bounded from below by the fibonacci sequence `nat.fib`.
 -- open `nat` as we will make use of fibonacci numbers.
 open Nat
 
+#print GeneralizedContinuedFraction.fib_le_of_continuantsAux_b /-
 theorem fib_le_of_continuantsAux_b :
     n ≤ 1 ∨ ¬(of v).TerminatedAt (n - 2) → (fib n : K) ≤ ((of v).continuantsAux n).b :=
   Nat.strong_induction_on n
@@ -251,7 +270,9 @@ theorem fib_le_of_continuantsAux_b :
         have : (0 : K) ≤ gp.b := le_trans zero_le_one one_le_gp_b
         mono)
 #align generalized_continued_fraction.fib_le_of_continuants_aux_b GeneralizedContinuedFraction.fib_le_of_continuantsAux_b
+-/
 
+#print GeneralizedContinuedFraction.succ_nth_fib_le_of_nth_denom /-
 /-- Shows that the `n`th denominator is greater than or equal to the `n + 1`th fibonacci number,
 that is `nat.fib (n + 1) ≤ Bₙ`. -/
 theorem succ_nth_fib_le_of_nth_denom (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
@@ -265,10 +286,12 @@ theorem succ_nth_fib_le_of_nth_denom (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n -
     case succ => exact Or.inr (Or.resolve_left hyp n.succ_ne_zero)
   exact fib_le_of_continuants_aux_b this
 #align generalized_continued_fraction.succ_nth_fib_le_of_nth_denom GeneralizedContinuedFraction.succ_nth_fib_le_of_nth_denom
+-/
 
 /-! As a simple consequence, we can now derive that all denominators are nonnegative. -/
 
 
+#print GeneralizedContinuedFraction.zero_le_of_continuantsAux_b /-
 theorem zero_le_of_continuantsAux_b : 0 ≤ ((of v).continuantsAux n).b :=
   by
   let g := of v
@@ -290,12 +313,16 @@ theorem zero_le_of_continuantsAux_b : 0 ≤ ((of v).continuantsAux n).b :=
           by exact_mod_cast (n + 1).fib.zero_le
         _ ≤ ((of v).continuantsAux (n + 1)).b := fib_le_of_continuants_aux_b (Or.inr not_terminated)
 #align generalized_continued_fraction.zero_le_of_continuants_aux_b GeneralizedContinuedFraction.zero_le_of_continuantsAux_b
+-/
 
+#print GeneralizedContinuedFraction.zero_le_of_denom /-
 /-- Shows that all denominators are nonnegative. -/
 theorem zero_le_of_denom : 0 ≤ (of v).denominators n := by
   rw [denom_eq_conts_b, nth_cont_eq_succ_nth_cont_aux]; exact zero_le_of_continuants_aux_b
 #align generalized_continued_fraction.zero_le_of_denom GeneralizedContinuedFraction.zero_le_of_denom
+-/
 
+#print GeneralizedContinuedFraction.le_of_succ_succ_get?_continuantsAux_b /-
 theorem le_of_succ_succ_get?_continuantsAux_b {b : K}
     (nth_part_denom_eq : (of v).partialDenominators.get? n = some b) :
     b * ((of v).continuantsAux <| n + 1).b ≤ ((of v).continuantsAux <| n + 2).b :=
@@ -305,7 +332,9 @@ theorem le_of_succ_succ_get?_continuantsAux_b {b : K}
   simp [of_part_num_eq_one (part_num_eq_s_a nth_s_eq), zero_le_of_continuants_aux_b,
     GeneralizedContinuedFraction.continuantsAux_recurrence nth_s_eq rfl rfl]
 #align generalized_continued_fraction.le_of_succ_succ_nth_continuants_aux_b GeneralizedContinuedFraction.le_of_succ_succ_get?_continuantsAux_b
+-/
 
+#print GeneralizedContinuedFraction.le_of_succ_get?_denom /-
 /-- Shows that `bₙ * Bₙ ≤ Bₙ₊₁`, where `bₙ` is the `n`th partial denominator and `Bₙ₊₁` and `Bₙ` are
 the `n + 1`th and `n`th denominator of the continued fraction. -/
 theorem le_of_succ_get?_denom {b : K}
@@ -315,7 +344,9 @@ theorem le_of_succ_get?_denom {b : K}
   rw [denom_eq_conts_b, nth_cont_eq_succ_nth_cont_aux]
   exact le_of_succ_succ_nth_continuants_aux_b nth_part_denom_eq
 #align generalized_continued_fraction.le_of_succ_nth_denom GeneralizedContinuedFraction.le_of_succ_get?_denom
+-/
 
+#print GeneralizedContinuedFraction.of_denom_mono /-
 /-- Shows that the sequence of denominators is monotone, that is `Bₙ ≤ Bₙ₊₁`. -/
 theorem of_denom_mono : (of v).denominators n ≤ (of v).denominators (n + 1) :=
   by
@@ -336,6 +367,7 @@ theorem of_denom_mono : (of v).denominators n ≤ (of v).denominators (n + 1) :=
         simpa using mul_le_mul_of_nonneg_right this zero_le_of_denom
       _ ≤ g.denominators (n + 1) := le_of_succ_nth_denom nth_part_denom_eq
 #align generalized_continued_fraction.of_denom_mono GeneralizedContinuedFraction.of_denom_mono
+-/
 
 section Determinant
 
@@ -347,6 +379,7 @@ Next we prove the so-called *determinant formula* for `generalized_continued_fra
 -/
 
 
+#print GeneralizedContinuedFraction.determinant_aux /-
 theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
     ((of v).continuantsAux n).a * ((of v).continuantsAux (n + 1)).b -
         ((of v).continuantsAux n).b * ((of v).continuantsAux (n + 1)).a =
@@ -391,7 +424,9 @@ theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
       ring
     exact IH <| Or.inr <| mt (terminated_stable <| n.sub_le 1) not_terminated_at_n
 #align generalized_continued_fraction.determinant_aux GeneralizedContinuedFraction.determinant_aux
+-/
 
+#print GeneralizedContinuedFraction.determinant /-
 /-- The determinant formula `Aₙ * Bₙ₊₁ - Bₙ * Aₙ₊₁ = (-1)^(n + 1)` -/
 theorem determinant (not_terminated_at_n : ¬(of v).TerminatedAt n) :
     (of v).numerators n * (of v).denominators (n + 1) -
@@ -399,6 +434,7 @@ theorem determinant (not_terminated_at_n : ¬(of v).TerminatedAt n) :
       (-1) ^ (n + 1) :=
   determinant_aux <| Or.inr <| not_terminated_at_n
 #align generalized_continued_fraction.determinant GeneralizedContinuedFraction.determinant
+-/
 
 end Determinant
 
@@ -412,6 +448,7 @@ position, i.e. bounds for the term `|v - (generalized_continued_fraction.of v).c
 -/
 
 
+#print GeneralizedContinuedFraction.sub_convergents_eq /-
 /-- This lemma follows from the finite correctness proof, the determinant equality, and
 by simplifying the difference. -/
 theorem sub_convergents_eq {ifp : IntFractPair K}
@@ -505,7 +542,9 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
       _ = (-1) ^ n / ((pB + ifp.fr⁻¹ * B) * B) := by rw [determinant_eq]
       _ = (-1) ^ n / (B * (ifp.fr⁻¹ * B + pB)) := by ac_rfl
 #align generalized_continued_fraction.sub_convergents_eq GeneralizedContinuedFraction.sub_convergents_eq
+-/
 
+#print GeneralizedContinuedFraction.abs_sub_convergents_le /-
 /-- Shows that `|v - Aₙ / Bₙ| ≤ 1 / (Bₙ * Bₙ₊₁)` -/
 theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
     |v - (of v).convergents n| ≤ 1 / ((of v).denominators n * ((of v).denominators <| n + 1)) :=
@@ -604,7 +643,9 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
     have : 0 ≤ conts.b := le_of_lt zero_lt_conts_b
     mono
 #align generalized_continued_fraction.abs_sub_convergents_le GeneralizedContinuedFraction.abs_sub_convergents_le
+-/
 
+#print GeneralizedContinuedFraction.abs_sub_convergents_le' /-
 /-- Shows that `|v - Aₙ / Bₙ| ≤ 1 / (bₙ * Bₙ * Bₙ)`. This bound is worse than the one shown in
 `gcf.abs_sub_convergents_le`, but sometimes it is easier to apply and sufficient for one's use case.
  -/
@@ -626,6 +667,7 @@ theorem abs_sub_convergents_le' {b : K}
     · conv_rhs => rw [mul_comm]
       exact mul_le_mul_of_nonneg_right (le_of_succ_nth_denom nth_part_denom_eq) hB.le
 #align generalized_continued_fraction.abs_sub_convergents_le' GeneralizedContinuedFraction.abs_sub_convergents_le'
+-/
 
 end ErrorTerm
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/893964fc28cefbcffc7cb784ed00a2895b4e65cf

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Kappelmann
 
 ! This file was ported from Lean 3 source module algebra.continued_fractions.computation.approximations
-! leanprover-community/mathlib commit a7e36e48519ab281320c4d192da6a7b348ce40ad
+! leanprover-community/mathlib commit cff8231f04dfa33fd8f2f45792eebd862ef30cad
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -15,6 +15,9 @@ import Mathbin.Tactic.SolveByElim
 /-!
 # Approximations for Continued Fraction Computations (`generalized_continued_fraction.of`)
 
+> THIS FILE IS SYNCHRONIZED WITH MATHLIB4.
+> Any changes to this file require a corresponding PR to mathlib4.
+
 ## Summary
 
 This file contains useful approximations for the values involved in the continued fractions

mathlib commit https://github.com/leanprover-community/mathlib/commit/7e5137f579de09a059a5ce98f364a04e221aabf0

@@ -286,7 +286,6 @@ theorem zero_le_of_continuantsAux_b : 0 ≤ ((of v).continuantsAux n).b :=
             fib (n + 1) :=
           by exact_mod_cast (n + 1).fib.zero_le
         _ ≤ ((of v).continuantsAux (n + 1)).b := fib_le_of_continuants_aux_b (Or.inr not_terminated)
-        
 #align generalized_continued_fraction.zero_le_of_continuants_aux_b GeneralizedContinuedFraction.zero_le_of_continuantsAux_b
 
 /-- Shows that all denominators are nonnegative. -/
@@ -333,7 +332,6 @@ theorem of_denom_mono : (of v).denominators n ≤ (of v).denominators (n + 1) :=
       g.denominators n ≤ b * g.denominators n := by
         simpa using mul_le_mul_of_nonneg_right this zero_le_of_denom
       _ ≤ g.denominators (n + 1) := le_of_succ_nth_denom nth_part_denom_eq
-      
 #align generalized_continued_fraction.of_denom_mono GeneralizedContinuedFraction.of_denom_mono
 
 section Determinant
@@ -383,7 +381,6 @@ theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
         by ring
       _ = pA * ppB - pB * ppA := by ring
       _ = (-1) ^ (n + 1) := by assumption
-      
     suffices ppA * pB - ppB * pA = (-1) ^ n
       by
       have pow_succ_n : (-1 : K) ^ (n + 1) = -1 * (-1) ^ n := pow_succ (-1) n
@@ -504,7 +501,6 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
       _ = (pA * B - pB * A) / ((pB + ifp.fr⁻¹ * B) * B) := by ring
       _ = (-1) ^ n / ((pB + ifp.fr⁻¹ * B) * B) := by rw [determinant_eq]
       _ = (-1) ^ n / (B * (ifp.fr⁻¹ * B + pB)) := by ac_rfl
-      
 #align generalized_continued_fraction.sub_convergents_eq GeneralizedContinuedFraction.sub_convergents_eq
 
 /-- Shows that `|v - Aₙ / Bₙ| ≤ 1 / (Bₙ * Bₙ₊₁)` -/

mathlib commit https://github.com/leanprover-community/mathlib/commit/cca40788df1b8755d5baf17ab2f27dacc2e17acb

@@ -168,7 +168,7 @@ theorem of_part_num_eq_one_and_exists_int_part_denom_eq {gp : GeneralizedContinu
     by
     have : (of v).s.get? n = some ⟨1, ifp.b⟩ :=
       nth_of_eq_some_of_succ_nth_int_fract_pair_stream stream_succ_nth_eq
-    have : some gp = some ⟨1, ifp.b⟩ := by rwa [nth_s_eq] at this
+    have : some gp = some ⟨1, ifp.b⟩ := by rwa [nth_s_eq] at this 
     injection this
   simp [this]
 #align generalized_continued_fraction.of_part_num_eq_one_and_exists_int_part_denom_eq GeneralizedContinuedFraction.of_part_num_eq_one_and_exists_int_part_denom_eq
@@ -180,7 +180,7 @@ theorem of_part_num_eq_one {a : K} (nth_part_num_eq : (of v).partialNumerators.g
   obtain ⟨gp, nth_s_eq, gp_a_eq_a_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.a = a;
   exact exists_s_a_of_part_num nth_part_num_eq
   have : gp.a = 1 := (of_part_num_eq_one_and_exists_int_part_denom_eq nth_s_eq).left
-  rwa [gp_a_eq_a_n] at this
+  rwa [gp_a_eq_a_n] at this 
 #align generalized_continued_fraction.of_part_num_eq_one GeneralizedContinuedFraction.of_part_num_eq_one
 
 /-- Shows that the partial denominators `bᵢ` correspond to an integer. -/
@@ -190,7 +190,7 @@ theorem exists_int_eq_of_part_denom {b : K}
   obtain ⟨gp, nth_s_eq, gp_b_eq_b_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.b = b;
   exact exists_s_b_of_part_denom nth_part_denom_eq
   have : ∃ z : ℤ, gp.b = (z : K) := (of_part_num_eq_one_and_exists_int_part_denom_eq nth_s_eq).right
-  rwa [gp_b_eq_b_n] at this
+  rwa [gp_b_eq_b_n] at this 
 #align generalized_continued_fraction.exists_int_eq_of_part_denom GeneralizedContinuedFraction.exists_int_eq_of_part_denom
 
 /-!
@@ -241,7 +241,7 @@ theorem fib_le_of_continuantsAux_b :
         suffices : (fib (n + 1) : K) ≤ gp.b * pconts.b
         solve_by_elim [add_le_add ppred_nth_fib_le_ppconts_B]
         -- finally use the fact that 1 ≤ gp.b to solve the goal
-        suffices 1 * (fib (n + 1) : K) ≤ gp.b * pconts.b by rwa [one_mul] at this
+        suffices 1 * (fib (n + 1) : K) ≤ gp.b * pconts.b by rwa [one_mul] at this 
         have one_le_gp_b : (1 : K) ≤ gp.b :=
           of_one_le_nth_part_denom (part_denom_eq_s_b s_ppred_nth_eq)
         have : (0 : K) ≤ fib (n + 1) := by exact_mod_cast (fib (n + 1)).zero_le
@@ -319,9 +319,10 @@ theorem of_denom_mono : (of v).denominators n ≤ (of v).denominators (n + 1) :=
   by
   let g := of v
   cases' Decidable.em <| g.partial_denominators.terminated_at n with terminated not_terminated
-  · have : g.partial_denominators.nth n = none := by rwa [Stream'.Seq.TerminatedAt] at terminated
+  · have : g.partial_denominators.nth n = none := by rwa [Stream'.Seq.TerminatedAt] at terminated 
     have : g.terminated_at n :=
-      terminated_at_iff_part_denom_none.elim_right (by rwa [Stream'.Seq.TerminatedAt] at terminated)
+      terminated_at_iff_part_denom_none.elim_right
+        (by rwa [Stream'.Seq.TerminatedAt] at terminated )
     have : g.denominators (n + 1) = g.denominators n :=
       denominators_stable_of_terminated n.le_succ this
     rw [this]
@@ -489,7 +490,7 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
       have : 0 < ifp.fr⁻¹ := by
         suffices 0 < ifp.fr by rwa [inv_pos]
         have : 0 ≤ ifp.fr := int_fract_pair.nth_stream_fr_nonneg stream_nth_eq
-        change ifp.fr ≠ 0 at ifp_fr_ne_zero
+        change ifp.fr ≠ 0 at ifp_fr_ne_zero 
         exact lt_of_le_of_ne this ifp_fr_ne_zero.symm
       have : 0 < ifp.fr⁻¹ * B := mul_pos this zero_lt_B
       have : 0 < pB + ifp.fr⁻¹ * B := add_pos_of_nonneg_of_pos zero_le_pB this
@@ -542,8 +543,8 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
       by
       -- apply `sub_convergens_eq` and simplify the result
       have tmp := sub_convergents_eq stream_nth_eq
-      delta at tmp
-      simp only [stream_nth_fr_ne_zero, conts_eq.symm, pred_conts_eq.symm] at tmp
+      delta at tmp 
+      simp only [stream_nth_fr_ne_zero, conts_eq.symm, pred_conts_eq.symm] at tmp 
       rw [tmp]
       simp only [denom']
       ring_nf
@@ -553,7 +554,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
     by
     have : (fib (n + 2) : K) ≤ nextConts.b :=
       fib_le_of_continuants_aux_b (Or.inr not_terminated_at_n)
-    rwa [nextConts_b_eq] at this
+    rwa [nextConts_b_eq] at this 
   have conts_b_ineq : (fib (n + 1) : K) ≤ conts.b :=
     haveI : ¬g.terminated_at (n - 1) := mt (terminated_stable n.pred_le) not_terminated_at_n
     fib_le_of_continuants_aux_b <| Or.inr this
@@ -579,7 +580,12 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
           haveI zero_le_ifp_n_fract : 0 ≤ ifp_n.fr :=
             int_fract_pair.nth_stream_fr_nonneg stream_nth_eq
           inv_pos.elim_right (lt_of_le_of_ne zero_le_ifp_n_fract stream_nth_fr_ne_zero.symm)
-        any_goals repeat' first |apply mul_pos|apply add_pos_of_nonneg_of_pos <;> assumption
+        any_goals
+            repeat'
+              first
+              | apply mul_pos
+              | apply add_pos_of_nonneg_of_pos <;>
+          assumption
       rwa [abs_of_pos this]
     rwa [this]
   suffices : 0 < denom ∧ denom ≤ denom';

mathlib commit https://github.com/leanprover-community/mathlib/commit/917c3c072e487b3cccdbfeff17e75b40e45f66cb

@@ -104,9 +104,7 @@ theorem one_le_succ_nth_stream_b {ifp_succ_n : IntFractPair K}
       int_fract_pair.stream v n = some ifp_n ∧
         ifp_n.fr ≠ 0 ∧ int_fract_pair.of ifp_n.fr⁻¹ = ifp_succ_n
   exact succ_nth_stream_eq_some_iff.elim_left succ_nth_stream_eq
-  suffices 1 ≤ ifp_n.fr⁻¹ by
-    rw_mod_cast [le_floor]
-    assumption
+  suffices 1 ≤ ifp_n.fr⁻¹ by rw_mod_cast [le_floor]; assumption
   suffices ifp_n.fr ≤ 1
     by
     have h : 0 < ifp_n.fr :=
@@ -128,8 +126,7 @@ theorem succ_nth_stream_b_le_nth_stream_fr_inv {ifp_n ifp_succ_n : IntFractPair
   suffices (⌊ifp_n.fr⁻¹⌋ : K) ≤ ifp_n.fr⁻¹
     by
     cases' ifp_n with _ ifp_n_fr
-    have : ifp_n_fr ≠ 0 := by
-      intro h
+    have : ifp_n_fr ≠ 0 := by intro h;
       simpa [h, int_fract_pair.stream, nth_stream_eq] using succ_nth_stream_eq
     have : int_fract_pair.of ifp_n_fr⁻¹ = ifp_succ_n := by
       simpa [this, int_fract_pair.stream, nth_stream_eq, Option.coe_def] using succ_nth_stream_eq
@@ -180,7 +177,7 @@ theorem of_part_num_eq_one_and_exists_int_part_denom_eq {gp : GeneralizedContinu
 theorem of_part_num_eq_one {a : K} (nth_part_num_eq : (of v).partialNumerators.get? n = some a) :
     a = 1 :=
   by
-  obtain ⟨gp, nth_s_eq, gp_a_eq_a_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.a = a
+  obtain ⟨gp, nth_s_eq, gp_a_eq_a_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.a = a;
   exact exists_s_a_of_part_num nth_part_num_eq
   have : gp.a = 1 := (of_part_num_eq_one_and_exists_int_part_denom_eq nth_s_eq).left
   rwa [gp_a_eq_a_n] at this
@@ -190,7 +187,7 @@ theorem of_part_num_eq_one {a : K} (nth_part_num_eq : (of v).partialNumerators.g
 theorem exists_int_eq_of_part_denom {b : K}
     (nth_part_denom_eq : (of v).partialDenominators.get? n = some b) : ∃ z : ℤ, b = (z : K) :=
   by
-  obtain ⟨gp, nth_s_eq, gp_b_eq_b_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.b = b
+  obtain ⟨gp, nth_s_eq, gp_b_eq_b_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.b = b;
   exact exists_s_b_of_part_denom nth_part_denom_eq
   have : ∃ z : ℤ, gp.b = (z : K) := (of_part_num_eq_one_and_exists_int_part_denom_eq nth_s_eq).right
   rwa [gp_b_eq_b_n] at this
@@ -221,7 +218,7 @@ theorem fib_le_of_continuantsAux_b :
         -- case 2 ≤ n
         have : ¬n + 2 ≤ 1 := by linarith
         have not_terminated_at_n : ¬g.terminated_at n := Or.resolve_left hyp this
-        obtain ⟨gp, s_ppred_nth_eq⟩ : ∃ gp, g.s.nth n = some gp
+        obtain ⟨gp, s_ppred_nth_eq⟩ : ∃ gp, g.s.nth n = some gp;
         exact option.ne_none_iff_exists'.mp not_terminated_at_n
         set pconts := g.continuants_aux (n + 1) with pconts_eq
         set ppconts := g.continuants_aux n with ppconts_eq
@@ -293,10 +290,8 @@ theorem zero_le_of_continuantsAux_b : 0 ≤ ((of v).continuantsAux n).b :=
 #align generalized_continued_fraction.zero_le_of_continuants_aux_b GeneralizedContinuedFraction.zero_le_of_continuantsAux_b
 
 /-- Shows that all denominators are nonnegative. -/
-theorem zero_le_of_denom : 0 ≤ (of v).denominators n :=
-  by
-  rw [denom_eq_conts_b, nth_cont_eq_succ_nth_cont_aux]
-  exact zero_le_of_continuants_aux_b
+theorem zero_le_of_denom : 0 ≤ (of v).denominators n := by
+  rw [denom_eq_conts_b, nth_cont_eq_succ_nth_cont_aux]; exact zero_le_of_continuants_aux_b
 #align generalized_continued_fraction.zero_le_of_denom GeneralizedContinuedFraction.zero_le_of_denom
 
 theorem le_of_succ_succ_get?_continuantsAux_b {b : K}
@@ -330,7 +325,7 @@ theorem of_denom_mono : (of v).denominators n ≤ (of v).denominators (n + 1) :=
     have : g.denominators (n + 1) = g.denominators n :=
       denominators_stable_of_terminated n.le_succ this
     rw [this]
-  · obtain ⟨b, nth_part_denom_eq⟩ : ∃ b, g.partial_denominators.nth n = some b
+  · obtain ⟨b, nth_part_denom_eq⟩ : ∃ b, g.partial_denominators.nth n = some b;
     exact option.ne_none_iff_exists'.mp not_terminated
     have : 1 ≤ b := of_one_le_nth_part_denom nth_part_denom_eq
     calc
@@ -371,7 +366,7 @@ theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
     -- let's change the goal to something more readable
     change pA * conts.b - pB * conts.a = (-1) ^ (n + 1)
     have not_terminated_at_n : ¬terminated_at g n := Or.resolve_left hyp n.succ_ne_zero
-    obtain ⟨gp, s_nth_eq⟩ : ∃ gp, g.s.nth n = some gp
+    obtain ⟨gp, s_nth_eq⟩ : ∃ gp, g.s.nth n = some gp;
     exact option.ne_none_iff_exists'.elim_left not_terminated_at_n
     -- unfold the recurrence relation for `conts` once and simplify to derive the following
     suffices pA * (ppB + gp.b * pB) - pB * (ppA + gp.b * pA) = (-1) ^ (n + 1)
@@ -380,7 +375,7 @@ theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
       have gp_a_eq_one : gp.a = 1 := of_part_num_eq_one (part_num_eq_s_a s_nth_eq)
       rw [gp_a_eq_one, this.symm]
       ring
-    suffices : pA * ppB - pB * ppA = (-1) ^ (n + 1)
+    suffices : pA * ppB - pB * ppA = (-1) ^ (n + 1);
     calc
       pA * (ppB + gp.b * pB) - pB * (ppA + gp.b * pA) =
           pA * ppB + pA * gp.b * pB - pB * ppA - pB * gp.b * pA :=
@@ -434,7 +429,7 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
     comp_exact_value_correctness_of_stream_eq_some stream_nth_eq
   cases' Decidable.em (ifp.fr = 0) with ifp_fr_eq_zero ifp_fr_ne_zero
   · suffices v - g.convergents n = 0 by simpa [ifp_fr_eq_zero]
-    replace g_finite_correctness : v = g.convergents n
+    replace g_finite_correctness : v = g.convergents n;
     · simpa [GeneralizedContinuedFraction.compExactValue, ifp_fr_eq_zero] using g_finite_correctness
     exact sub_eq_zero.elim_right g_finite_correctness
   · -- more shorthand notation
@@ -445,7 +440,7 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
     -- first, let's simplify the goal as `ifp.fr ≠ 0`
     suffices v - A / B = (-1) ^ n / (B * (ifp.fr⁻¹ * B + pB)) by simpa [ifp_fr_ne_zero]
     -- now we can unfold `g.comp_exact_value` to derive the following equality for `v`
-    replace g_finite_correctness : v = (pA + ifp.fr⁻¹ * A) / (pB + ifp.fr⁻¹ * B)
+    replace g_finite_correctness : v = (pA + ifp.fr⁻¹ * A) / (pB + ifp.fr⁻¹ * B);
     ·
       simpa [GeneralizedContinuedFraction.compExactValue, ifp_fr_ne_zero, next_continuants,
         next_numerator, next_denominator, add_comm] using g_finite_correctness
@@ -522,7 +517,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
   set pred_conts := continuants_aux g n with pred_conts_eq
   -- change the goal to something more readable
   change |v - convergents g n| ≤ 1 / (conts.b * nextConts.b)
-  obtain ⟨gp, s_nth_eq⟩ : ∃ gp, g.s.nth n = some gp
+  obtain ⟨gp, s_nth_eq⟩ : ∃ gp, g.s.nth n = some gp;
   exact option.ne_none_iff_exists'.elim_left not_terminated_at_n
   have gp_a_eq_one : gp.a = 1 := of_part_num_eq_one (part_num_eq_s_a s_nth_eq)
   -- unfold the recurrence relation for `nextConts.b`
@@ -530,10 +525,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
     simp [nextConts, continuants_aux_recurrence s_nth_eq pred_conts_eq conts_eq, gp_a_eq_one,
       pred_conts_eq.symm, conts_eq.symm, add_comm]
   let denom := conts.b * (pred_conts.b + gp.b * conts.b)
-  suffices |v - g.convergents n| ≤ 1 / denom
-    by
-    rw [nextConts_b_eq]
-    congr 1
+  suffices |v - g.convergents n| ≤ 1 / denom by rw [nextConts_b_eq]; congr 1
   obtain ⟨ifp_succ_n, succ_nth_stream_eq, ifp_succ_n_b_eq_gp_b⟩ :
     ∃ ifp_succ_n, int_fract_pair.stream v (n + 1) = some ifp_succ_n ∧ (ifp_succ_n.b : K) = gp.b
   exact int_fract_pair.exists_succ_nth_stream_of_gcf_of_nth_eq_some s_nth_eq
@@ -590,7 +582,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
         any_goals repeat' first |apply mul_pos|apply add_pos_of_nonneg_of_pos <;> assumption
       rwa [abs_of_pos this]
     rwa [this]
-  suffices : 0 < denom ∧ denom ≤ denom'
+  suffices : 0 < denom ∧ denom ≤ denom';
   exact div_le_div_of_le_left zero_le_one this.left this.right
   constructor
   · have : 0 < pred_conts.b + gp.b * conts.b :=
@@ -599,7 +591,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
         nextConts_b_ineq
     solve_by_elim [mul_pos]
   · -- we can cancel multiplication by `conts.b` and addition with `pred_conts.b`
-    suffices : gp.b * conts.b ≤ ifp_n.fr⁻¹ * conts.b
+    suffices : gp.b * conts.b ≤ ifp_n.fr⁻¹ * conts.b;
     exact (mul_le_mul_left zero_lt_conts_b).right <| (add_le_add_iff_left pred_conts.b).right this
     suffices (ifp_succ_n.b : K) * conts.b ≤ ifp_n.fr⁻¹ * conts.b by rwa [← ifp_succ_n_b_eq_gp_b]
     have : (ifp_succ_n.b : K) ≤ ifp_n.fr⁻¹ :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/e05ead7993520a432bec94ac504842d90707ad63

@@ -146,7 +146,7 @@ fraction `generalized_continued_fraction.of`.
 
 
 /-- Shows that the integer parts of the continued fraction are at least one. -/
-theorem of_one_le_nth_part_denom {b : K}
+theorem of_one_le_get?_part_denom {b : K}
     (nth_part_denom_eq : (of v).partialDenominators.get? n = some b) : 1 ≤ b :=
   by
   obtain ⟨gp_n, nth_s_eq, ⟨-⟩⟩ : ∃ gp_n, (of v).s.get? n = some gp_n ∧ gp_n.b = b;
@@ -156,7 +156,7 @@ theorem of_one_le_nth_part_denom {b : K}
   exact int_fract_pair.exists_succ_nth_stream_of_gcf_of_nth_eq_some nth_s_eq
   rw [← ifp_n_b_eq_gp_n_b]
   exact_mod_cast int_fract_pair.one_le_succ_nth_stream_b succ_nth_stream_eq
-#align generalized_continued_fraction.of_one_le_nth_part_denom GeneralizedContinuedFraction.of_one_le_nth_part_denom
+#align generalized_continued_fraction.of_one_le_nth_part_denom GeneralizedContinuedFraction.of_one_le_get?_part_denom
 
 /--
 Shows that the partial numerators `aᵢ` of the continued fraction are equal to one and the partial
@@ -299,7 +299,7 @@ theorem zero_le_of_denom : 0 ≤ (of v).denominators n :=
   exact zero_le_of_continuants_aux_b
 #align generalized_continued_fraction.zero_le_of_denom GeneralizedContinuedFraction.zero_le_of_denom
 
-theorem le_of_succ_succ_nth_continuantsAux_b {b : K}
+theorem le_of_succ_succ_get?_continuantsAux_b {b : K}
     (nth_part_denom_eq : (of v).partialDenominators.get? n = some b) :
     b * ((of v).continuantsAux <| n + 1).b ≤ ((of v).continuantsAux <| n + 2).b :=
   by
@@ -307,17 +307,17 @@ theorem le_of_succ_succ_nth_continuantsAux_b {b : K}
   exact exists_s_b_of_part_denom nth_part_denom_eq
   simp [of_part_num_eq_one (part_num_eq_s_a nth_s_eq), zero_le_of_continuants_aux_b,
     GeneralizedContinuedFraction.continuantsAux_recurrence nth_s_eq rfl rfl]
-#align generalized_continued_fraction.le_of_succ_succ_nth_continuants_aux_b GeneralizedContinuedFraction.le_of_succ_succ_nth_continuantsAux_b
+#align generalized_continued_fraction.le_of_succ_succ_nth_continuants_aux_b GeneralizedContinuedFraction.le_of_succ_succ_get?_continuantsAux_b
 
 /-- Shows that `bₙ * Bₙ ≤ Bₙ₊₁`, where `bₙ` is the `n`th partial denominator and `Bₙ₊₁` and `Bₙ` are
 the `n + 1`th and `n`th denominator of the continued fraction. -/
-theorem le_of_succ_nth_denom {b : K}
+theorem le_of_succ_get?_denom {b : K}
     (nth_part_denom_eq : (of v).partialDenominators.get? n = some b) :
     b * (of v).denominators n ≤ (of v).denominators (n + 1) :=
   by
   rw [denom_eq_conts_b, nth_cont_eq_succ_nth_cont_aux]
   exact le_of_succ_succ_nth_continuants_aux_b nth_part_denom_eq
-#align generalized_continued_fraction.le_of_succ_nth_denom GeneralizedContinuedFraction.le_of_succ_nth_denom
+#align generalized_continued_fraction.le_of_succ_nth_denom GeneralizedContinuedFraction.le_of_succ_get?_denom
 
 /-- Shows that the sequence of denominators is monotone, that is `Bₙ ≤ Bₙ₊₁`. -/
 theorem of_denom_mono : (of v).denominators n ≤ (of v).denominators (n + 1) :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/b685f506164f8d17a6404048bc4d696739c5d976

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Kappelmann
 
 ! This file was ported from Lean 3 source module algebra.continued_fractions.computation.approximations
-! leanprover-community/mathlib commit c85b4d15cfdac3abffce2f449e228a0cf0326912
+! leanprover-community/mathlib commit a7e36e48519ab281320c4d192da6a7b348ce40ad
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -324,9 +324,9 @@ theorem of_denom_mono : (of v).denominators n ≤ (of v).denominators (n + 1) :=
   by
   let g := of v
   cases' Decidable.em <| g.partial_denominators.terminated_at n with terminated not_terminated
-  · have : g.partial_denominators.nth n = none := by rwa [SeqCat.TerminatedAt] at terminated
+  · have : g.partial_denominators.nth n = none := by rwa [Stream'.Seq.TerminatedAt] at terminated
     have : g.terminated_at n :=
-      terminated_at_iff_part_denom_none.elim_right (by rwa [SeqCat.TerminatedAt] at terminated)
+      terminated_at_iff_part_denom_none.elim_right (by rwa [Stream'.Seq.TerminatedAt] at terminated)
     have : g.denominators (n + 1) = g.denominators n :=
       denominators_stable_of_terminated n.le_succ this
     rw [this]

mathlib commit https://github.com/leanprover-community/mathlib/commit/3180fab693e2cee3bff62675571264cb8778b212

@@ -622,7 +622,7 @@ theorem abs_sub_convergents_le' {b : K}
   -- to consider the case `(generalized_continued_fraction.of v).denominators n = 0`.
   rcases zero_le_of_denom.eq_or_gt with
     ((hB : (GeneralizedContinuedFraction.of v).denominators n = 0) | hB)
-  · simp only [hB, mul_zero, zero_mul, div_zero]
+  · simp only [hB, MulZeroClass.mul_zero, MulZeroClass.zero_mul, div_zero]
   · apply one_div_le_one_div_of_le
     · have : 0 < b := zero_lt_one.trans_le (of_one_le_nth_part_denom nth_part_denom_eq)
       apply_rules [mul_pos]

mathlib commit https://github.com/leanprover-community/mathlib/commit/bd9851ca476957ea4549eb19b40e7b5ade9428cc

A PR accompanying #12339.

Zulip discussion

@@ -97,7 +97,7 @@ theorem one_le_succ_nth_stream_b {ifp_succ_n : IntFractPair K}
   obtain ⟨ifp_n, nth_stream_eq, stream_nth_fr_ne_zero, ⟨-⟩⟩ :
     ∃ ifp_n,
       IntFractPair.stream v n = some ifp_n ∧ ifp_n.fr ≠ 0 ∧ IntFractPair.of ifp_n.fr⁻¹ = ifp_succ_n
-  exact succ_nth_stream_eq_some_iff.1 succ_nth_stream_eq
+  · exact succ_nth_stream_eq_some_iff.1 succ_nth_stream_eq
   suffices 1 ≤ ifp_n.fr⁻¹ by rwa [IntFractPair.of, le_floor, cast_one]
   suffices ifp_n.fr ≤ 1 by
     have h : 0 < ifp_n.fr :=
@@ -474,7 +474,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
   obtain ⟨ifp_n, stream_nth_eq, stream_nth_fr_ne_zero, if_of_eq_ifp_succ_n⟩ :
     ∃ ifp_n,
       IntFractPair.stream v n = some ifp_n ∧ ifp_n.fr ≠ 0 ∧ IntFractPair.of ifp_n.fr⁻¹ = ifp_succ_n
-  exact IntFractPair.succ_nth_stream_eq_some_iff.1 succ_nth_stream_eq
+  · exact IntFractPair.succ_nth_stream_eq_some_iff.1 succ_nth_stream_eq
   let denom' := conts.b * (pred_conts.b + ifp_n.fr⁻¹ * conts.b)
   -- now we can use `sub_convergents_eq` to simplify our goal
   suffices |(-1) ^ n / denom'| ≤ 1 / denom by

We change the following field in the definition of an additive commutative monoid:

 nsmul_succ : ∀ (n : ℕ) (x : G),
-  AddMonoid.nsmul (n + 1) x = x + AddMonoid.nsmul n x
+  AddMonoid.nsmul (n + 1) x = AddMonoid.nsmul n x + x

where the latter is more natural

We adjust the definitions of ^ in monoids, groups, etc. Originally there was a warning comment about why this natural order was preferred

use x * npowRec n x and not npowRec n x * x in the definition to make sure that definitional unfolding of npowRec is blocked, to avoid deep recursion issues.

but it seems to no longer apply.

Remarks on the PR :

• pow_succ and pow_succ' have switched their meanings.
• Most of the time, the proofs were adjusted by priming/unpriming one lemma, or exchanging left and right; a few proofs were more complicated to adjust.
• In particular, [Mathlib/NumberTheory/RamificationInertia.lean] used Ideal.IsPrime.mul_mem_pow which is defined in [Mathlib/RingTheory/DedekindDomain/Ideal.lean]. Changing the order of operation forced me to add the symmetric lemma Ideal.IsPrime.mem_pow_mul.
• the docstring for Cauchy condensation test in [Mathlib/Analysis/PSeries.lean] was mathematically incorrect, I added the mention that the function is antitone.

@@ -349,7 +349,7 @@ theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
       _ = pA * ppB - pB * ppA := by ring
       _ = (-1) ^ (n + 1) := by assumption
     suffices ppA * pB - ppB * pA = (-1) ^ n by
-      have pow_succ_n : (-1 : K) ^ (n + 1) = -1 * (-1) ^ n := pow_succ (-1) n
+      have pow_succ_n : (-1 : K) ^ (n + 1) = -1 * (-1) ^ n := pow_succ' (-1) n
       rw [pow_succ_n, ← this]
       ring
     exact IH <| Or.inr <| mt (terminated_stable <| n.sub_le 1) not_terminated_at_n

The new names and argument orders match the corresponding * lemmas, which I already took care of in a previous PR.

From LeanAPAP

@@ -514,7 +514,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
         positivity
       rw [abs_of_pos this]
     rwa [this]
-  suffices 0 < denom ∧ denom ≤ denom' from div_le_div_of_le_left zero_le_one this.left this.right
+  suffices 0 < denom ∧ denom ≤ denom' from div_le_div_of_nonneg_left zero_le_one this.1 this.2
   constructor
   · have : 0 < pred_conts.b + gp.b * conts.b :=
       nextConts_b_ineq.trans_lt' <| mod_cast fib_pos.2 <| succ_pos _

Homogenises porting notes via capitalisation and addition of whitespace.

It makes the following changes:

• converts "--porting note" into "-- Porting note";
• converts "porting note" into "Porting note".

@@ -526,7 +526,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
     have : (ifp_succ_n.b : K) ≤ ifp_n.fr⁻¹ :=
       IntFractPair.succ_nth_stream_b_le_nth_stream_fr_inv stream_nth_eq succ_nth_stream_eq
     have : 0 ≤ conts.b := le_of_lt zero_lt_conts_b
-    -- porting note: was `mono`
+    -- Porting note: was `mono`
     refine' mul_le_mul_of_nonneg_right _ _ <;> assumption
 #align generalized_continued_fraction.abs_sub_convergents_le GeneralizedContinuedFraction.abs_sub_convergents_le
 

I ran tryAtEachStep on all files under Mathlib to find all locations where omega succeeds. For each that was a linarith without an only, I tried replacing it with omega, and I verified that elaboration time got smaller. (In almost all cases, there was a noticeable speedup.) I also replaced some slow aesops along the way.

@@ -199,7 +199,7 @@ theorem fib_le_of_continuantsAux_b :
       · simp [fib_add_two, continuantsAux] -- case n = 0
       · simp [fib_add_two, continuantsAux] -- case n = 1
       · let g := of v -- case 2 ≤ n
-        have : ¬n + 2 ≤ 1 := by linarith
+        have : ¬n + 2 ≤ 1 := by omega
         have not_terminated_at_n : ¬g.TerminatedAt n := Or.resolve_left hyp this
         obtain ⟨gp, s_ppred_nth_eq⟩ : ∃ gp, g.s.get? n = some gp :=
           Option.ne_none_iff_exists'.mp not_terminated_at_n

This covers many instances, but is not exhaustive.

Independently of whether that syntax should be avoided (similar to #10534), I think all these changes are small improvements.

@@ -137,11 +137,11 @@ fraction `GeneralizedContinuedFraction.of`.
 /-- Shows that the integer parts of the continued fraction are at least one. -/
 theorem of_one_le_get?_part_denom {b : K}
     (nth_part_denom_eq : (of v).partialDenominators.get? n = some b) : 1 ≤ b := by
-  obtain ⟨gp_n, nth_s_eq, ⟨-⟩⟩ : ∃ gp_n, (of v).s.get? n = some gp_n ∧ gp_n.b = b;
-  exact exists_s_b_of_part_denom nth_part_denom_eq
+  obtain ⟨gp_n, nth_s_eq, ⟨-⟩⟩ : ∃ gp_n, (of v).s.get? n = some gp_n ∧ gp_n.b = b :=
+    exists_s_b_of_part_denom nth_part_denom_eq
   obtain ⟨ifp_n, succ_nth_stream_eq, ifp_n_b_eq_gp_n_b⟩ :
-    ∃ ifp, IntFractPair.stream v (n + 1) = some ifp ∧ (ifp.b : K) = gp_n.b
-  exact IntFractPair.exists_succ_get?_stream_of_gcf_of_get?_eq_some nth_s_eq
+      ∃ ifp, IntFractPair.stream v (n + 1) = some ifp ∧ (ifp.b : K) = gp_n.b :=
+    IntFractPair.exists_succ_get?_stream_of_gcf_of_get?_eq_some nth_s_eq
   rw [← ifp_n_b_eq_gp_n_b]
   exact mod_cast IntFractPair.one_le_succ_nth_stream_b succ_nth_stream_eq
 #align generalized_continued_fraction.of_one_le_nth_part_denom GeneralizedContinuedFraction.of_one_le_get?_part_denom
@@ -152,8 +152,8 @@ denominators `bᵢ` correspond to integers.
 -/
 theorem of_part_num_eq_one_and_exists_int_part_denom_eq {gp : GeneralizedContinuedFraction.Pair K}
     (nth_s_eq : (of v).s.get? n = some gp) : gp.a = 1 ∧ ∃ z : ℤ, gp.b = (z : K) := by
-  obtain ⟨ifp, stream_succ_nth_eq, -⟩ : ∃ ifp, IntFractPair.stream v (n + 1) = some ifp ∧ _
-  exact IntFractPair.exists_succ_get?_stream_of_gcf_of_get?_eq_some nth_s_eq
+  obtain ⟨ifp, stream_succ_nth_eq, -⟩ : ∃ ifp, IntFractPair.stream v (n + 1) = some ifp ∧ _ :=
+    IntFractPair.exists_succ_get?_stream_of_gcf_of_get?_eq_some nth_s_eq
   have : gp = ⟨1, ifp.b⟩ := by
     have : (of v).s.get? n = some ⟨1, ifp.b⟩ :=
       get?_of_eq_some_of_succ_get?_intFractPair_stream stream_succ_nth_eq
@@ -165,8 +165,8 @@ theorem of_part_num_eq_one_and_exists_int_part_denom_eq {gp : GeneralizedContinu
 /-- Shows that the partial numerators `aᵢ` are equal to one. -/
 theorem of_part_num_eq_one {a : K} (nth_part_num_eq : (of v).partialNumerators.get? n = some a) :
     a = 1 := by
-  obtain ⟨gp, nth_s_eq, gp_a_eq_a_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.a = a;
-  exact exists_s_a_of_part_num nth_part_num_eq
+  obtain ⟨gp, nth_s_eq, gp_a_eq_a_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.a = a :=
+    exists_s_a_of_part_num nth_part_num_eq
   have : gp.a = 1 := (of_part_num_eq_one_and_exists_int_part_denom_eq nth_s_eq).left
   rwa [gp_a_eq_a_n] at this
 #align generalized_continued_fraction.of_part_num_eq_one GeneralizedContinuedFraction.of_part_num_eq_one
@@ -174,8 +174,8 @@ theorem of_part_num_eq_one {a : K} (nth_part_num_eq : (of v).partialNumerators.g
 /-- Shows that the partial denominators `bᵢ` correspond to an integer. -/
 theorem exists_int_eq_of_part_denom {b : K}
     (nth_part_denom_eq : (of v).partialDenominators.get? n = some b) : ∃ z : ℤ, b = (z : K) := by
-  obtain ⟨gp, nth_s_eq, gp_b_eq_b_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.b = b;
-  exact exists_s_b_of_part_denom nth_part_denom_eq
+  obtain ⟨gp, nth_s_eq, gp_b_eq_b_n⟩ : ∃ gp, (of v).s.get? n = some gp ∧ gp.b = b :=
+    exists_s_b_of_part_denom nth_part_denom_eq
   have : ∃ z : ℤ, gp.b = (z : K) := (of_part_num_eq_one_and_exists_int_part_denom_eq nth_s_eq).right
   rwa [gp_b_eq_b_n] at this
 #align generalized_continued_fraction.exists_int_eq_of_part_denom GeneralizedContinuedFraction.exists_int_eq_of_part_denom
@@ -201,8 +201,8 @@ theorem fib_le_of_continuantsAux_b :
       · let g := of v -- case 2 ≤ n
         have : ¬n + 2 ≤ 1 := by linarith
         have not_terminated_at_n : ¬g.TerminatedAt n := Or.resolve_left hyp this
-        obtain ⟨gp, s_ppred_nth_eq⟩ : ∃ gp, g.s.get? n = some gp
-        exact Option.ne_none_iff_exists'.mp not_terminated_at_n
+        obtain ⟨gp, s_ppred_nth_eq⟩ : ∃ gp, g.s.get? n = some gp :=
+          Option.ne_none_iff_exists'.mp not_terminated_at_n
         set pconts := g.continuantsAux (n + 1) with pconts_eq
         set ppconts := g.continuantsAux n with ppconts_eq
         -- use the recurrence of `continuantsAux`
@@ -273,8 +273,8 @@ theorem zero_le_of_denom : 0 ≤ (of v).denominators n := by
 theorem le_of_succ_succ_get?_continuantsAux_b {b : K}
     (nth_part_denom_eq : (of v).partialDenominators.get? n = some b) :
     b * ((of v).continuantsAux <| n + 1).b ≤ ((of v).continuantsAux <| n + 2).b := by
-  obtain ⟨gp_n, nth_s_eq, rfl⟩ : ∃ gp_n, (of v).s.get? n = some gp_n ∧ gp_n.b = b
-  exact exists_s_b_of_part_denom nth_part_denom_eq
+  obtain ⟨gp_n, nth_s_eq, rfl⟩ : ∃ gp_n, (of v).s.get? n = some gp_n ∧ gp_n.b = b :=
+    exists_s_b_of_part_denom nth_part_denom_eq
   simp [of_part_num_eq_one (part_num_eq_s_a nth_s_eq), zero_le_of_continuantsAux_b,
     GeneralizedContinuedFraction.continuantsAux_recurrence nth_s_eq rfl rfl]
 #align generalized_continued_fraction.le_of_succ_succ_nth_continuants_aux_b GeneralizedContinuedFraction.le_of_succ_succ_get?_continuantsAux_b
@@ -298,8 +298,8 @@ theorem of_denom_mono : (of v).denominators n ≤ (of v).denominators (n + 1) :=
     have : g.denominators (n + 1) = g.denominators n :=
       denominators_stable_of_terminated n.le_succ this
     rw [this]
-  · obtain ⟨b, nth_part_denom_eq⟩ : ∃ b, g.partialDenominators.get? n = some b
-    exact Option.ne_none_iff_exists'.mp not_terminated
+  · obtain ⟨b, nth_part_denom_eq⟩ : ∃ b, g.partialDenominators.get? n = some b :=
+      Option.ne_none_iff_exists'.mp not_terminated
     have : 1 ≤ b := of_one_le_get?_part_denom nth_part_denom_eq
     calc
       g.denominators n ≤ b * g.denominators n := by
@@ -335,8 +335,8 @@ theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
     -- let's change the goal to something more readable
     change pA * conts.b - pB * conts.a = (-1) ^ (n + 1)
     have not_terminated_at_n : ¬TerminatedAt g n := Or.resolve_left hyp n.succ_ne_zero
-    obtain ⟨gp, s_nth_eq⟩ : ∃ gp, g.s.get? n = some gp
-    exact Option.ne_none_iff_exists'.1 not_terminated_at_n
+    obtain ⟨gp, s_nth_eq⟩ : ∃ gp, g.s.get? n = some gp :=
+      Option.ne_none_iff_exists'.1 not_terminated_at_n
     -- unfold the recurrence relation for `conts` once and simplify to derive the following
     suffices pA * (ppB + gp.b * pB) - pB * (ppA + gp.b * pA) = (-1) ^ (n + 1) by
       simp only [conts, continuantsAux_recurrence s_nth_eq ppred_conts_eq pred_conts_eq]
@@ -459,8 +459,8 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
   set pred_conts := continuantsAux g n with pred_conts_eq
   -- change the goal to something more readable
   change |v - convergents g n| ≤ 1 / (conts.b * nextConts.b)
-  obtain ⟨gp, s_nth_eq⟩ : ∃ gp, g.s.get? n = some gp
-  exact Option.ne_none_iff_exists'.1 not_terminated_at_n
+  obtain ⟨gp, s_nth_eq⟩ : ∃ gp, g.s.get? n = some gp :=
+    Option.ne_none_iff_exists'.1 not_terminated_at_n
   have gp_a_eq_one : gp.a = 1 := of_part_num_eq_one (part_num_eq_s_a s_nth_eq)
   -- unfold the recurrence relation for `nextConts.b`
   have nextConts_b_eq : nextConts.b = pred_conts.b + gp.b * conts.b := by
@@ -469,8 +469,8 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
   let denom := conts.b * (pred_conts.b + gp.b * conts.b)
   suffices |v - g.convergents n| ≤ 1 / denom by rw [nextConts_b_eq]; congr 1
   obtain ⟨ifp_succ_n, succ_nth_stream_eq, ifp_succ_n_b_eq_gp_b⟩ :
-    ∃ ifp_succ_n, IntFractPair.stream v (n + 1) = some ifp_succ_n ∧ (ifp_succ_n.b : K) = gp.b
-  exact IntFractPair.exists_succ_get?_stream_of_gcf_of_get?_eq_some s_nth_eq
+      ∃ ifp_succ_n, IntFractPair.stream v (n + 1) = some ifp_succ_n ∧ (ifp_succ_n.b : K) = gp.b :=
+    IntFractPair.exists_succ_get?_stream_of_gcf_of_get?_eq_some s_nth_eq
   obtain ⟨ifp_n, stream_nth_eq, stream_nth_fr_ne_zero, if_of_eq_ifp_succ_n⟩ :
     ∃ ifp_n,
       IntFractPair.stream v n = some ifp_n ∧ ifp_n.fr ≠ 0 ∧ IntFractPair.of ifp_n.fr⁻¹ = ifp_succ_n

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

@@ -7,7 +7,6 @@ import Mathlib.Algebra.ContinuedFractions.Computation.CorrectnessTerminating
 import Mathlib.Data.Nat.Fib.Basic
 import Mathlib.Tactic.Monotonicity
 import Mathlib.Algebra.GroupPower.Order
-import Std.Tactic.SolveByElim
 
 #align_import algebra.continued_fractions.computation.approximations from "leanprover-community/mathlib"@"a7e36e48519ab281320c4d192da6a7b348ce40ad"
 
@@ -340,7 +339,7 @@ theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
     exact Option.ne_none_iff_exists'.1 not_terminated_at_n
     -- unfold the recurrence relation for `conts` once and simplify to derive the following
     suffices pA * (ppB + gp.b * pB) - pB * (ppA + gp.b * pA) = (-1) ^ (n + 1) by
-      simp only [continuantsAux_recurrence s_nth_eq ppred_conts_eq pred_conts_eq]
+      simp only [conts, continuantsAux_recurrence s_nth_eq ppred_conts_eq pred_conts_eq]
       have gp_a_eq_one : gp.a = 1 := of_part_num_eq_one (part_num_eq_s_a s_nth_eq)
       rw [gp_a_eq_one, this.symm]
       ring
@@ -465,7 +464,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
   have gp_a_eq_one : gp.a = 1 := of_part_num_eq_one (part_num_eq_s_a s_nth_eq)
   -- unfold the recurrence relation for `nextConts.b`
   have nextConts_b_eq : nextConts.b = pred_conts.b + gp.b * conts.b := by
-    simp [continuantsAux_recurrence s_nth_eq pred_conts_eq conts_eq, gp_a_eq_one,
+    simp [nextConts, continuantsAux_recurrence s_nth_eq pred_conts_eq conts_eq, gp_a_eq_one,
       pred_conts_eq.symm, conts_eq.symm, add_comm]
   let denom := conts.b * (pred_conts.b + gp.b * conts.b)
   suffices |v - g.convergents n| ≤ 1 / denom by rw [nextConts_b_eq]; congr 1

No changes to tactic file, it's just boring fixes throughout the library.

This follows on from #6964.

Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr> Co-authored-by: Eric Wieser <wieser.eric@gmail.com>

@@ -220,8 +220,8 @@ theorem fib_le_of_continuantsAux_b :
         -- use the IH to get the inequalities for `pconts` and `ppconts`
         have ppred_nth_fib_le_ppconts_B : (fib n : K) ≤ ppconts.b :=
           IH n (lt_trans (Nat.lt.base n) <| Nat.lt.base <| n + 1) (Or.inr not_terminated_at_ppred_n)
-        suffices : (fib (n + 1) : K) ≤ gp.b * pconts.b
-        solve_by_elim [_root_.add_le_add ppred_nth_fib_le_ppconts_B]
+        suffices (fib (n + 1) : K) ≤ gp.b * pconts.b by
+          solve_by_elim [_root_.add_le_add ppred_nth_fib_le_ppconts_B]
         -- finally use the fact that `1 ≤ gp.b` to solve the goal
         suffices 1 * (fib (n + 1) : K) ≤ gp.b * pconts.b by rwa [one_mul] at this
         have one_le_gp_b : (1 : K) ≤ gp.b :=
@@ -344,8 +344,7 @@ theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
       have gp_a_eq_one : gp.a = 1 := of_part_num_eq_one (part_num_eq_s_a s_nth_eq)
       rw [gp_a_eq_one, this.symm]
       ring
-    suffices : pA * ppB - pB * ppA = (-1) ^ (n + 1);
-    calc
+    suffices pA * ppB - pB * ppA = (-1) ^ (n + 1) by calc
       pA * (ppB + gp.b * pB) - pB * (ppA + gp.b * pA) =
           pA * ppB + pA * gp.b * pB - pB * ppA - pB * gp.b * pA := by ring
       _ = pA * ppB - pB * ppA := by ring
@@ -393,8 +392,8 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
     compExactValue_correctness_of_stream_eq_some stream_nth_eq
   obtain (ifp_fr_eq_zero | ifp_fr_ne_zero) := eq_or_ne ifp.fr 0
   · suffices v - g.convergents n = 0 by simpa [ifp_fr_eq_zero]
-    replace g_finite_correctness : v = g.convergents n;
-    · simpa [GeneralizedContinuedFraction.compExactValue, ifp_fr_eq_zero] using g_finite_correctness
+    replace g_finite_correctness : v = g.convergents n := by
+      simpa [GeneralizedContinuedFraction.compExactValue, ifp_fr_eq_zero] using g_finite_correctness
     exact sub_eq_zero.2 g_finite_correctness
   · -- more shorthand notation
     let A := conts.a
@@ -404,8 +403,8 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
     -- first, let's simplify the goal as `ifp.fr ≠ 0`
     suffices v - A / B = (-1) ^ n / (B * (ifp.fr⁻¹ * B + pB)) by simpa [ifp_fr_ne_zero]
     -- now we can unfold `g.compExactValue` to derive the following equality for `v`
-    replace g_finite_correctness : v = (pA + ifp.fr⁻¹ * A) / (pB + ifp.fr⁻¹ * B)
-    · simpa [GeneralizedContinuedFraction.compExactValue, ifp_fr_ne_zero, nextContinuants,
+    replace g_finite_correctness : v = (pA + ifp.fr⁻¹ * A) / (pB + ifp.fr⁻¹ * B) := by
+      simpa [GeneralizedContinuedFraction.compExactValue, ifp_fr_ne_zero, nextContinuants,
         nextNumerator, nextDenominator, add_comm] using g_finite_correctness
     -- let's rewrite this equality for `v` in our goal
     suffices
@@ -522,8 +521,8 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
       nextConts_b_ineq.trans_lt' <| mod_cast fib_pos.2 <| succ_pos _
     solve_by_elim [mul_pos]
   · -- we can cancel multiplication by `conts.b` and addition with `pred_conts.b`
-    suffices : gp.b * conts.b ≤ ifp_n.fr⁻¹ * conts.b
-    exact (mul_le_mul_left zero_lt_conts_b).2 <| (add_le_add_iff_left pred_conts.b).2 this
+    suffices gp.b * conts.b ≤ ifp_n.fr⁻¹ * conts.b from
+      (mul_le_mul_left zero_lt_conts_b).2 <| (add_le_add_iff_left pred_conts.b).2 this
     suffices (ifp_succ_n.b : K) * conts.b ≤ ifp_n.fr⁻¹ * conts.b by rwa [← ifp_succ_n_b_eq_gp_b]
     have : (ifp_succ_n.b : K) ≤ ifp_n.fr⁻¹ :=
       IntFractPair.succ_nth_stream_b_le_nth_stream_fr_inv stream_nth_eq succ_nth_stream_eq

cherry-picked from #9347

Co-Authored-By: @digama0

@@ -6,6 +6,7 @@ Authors: Kevin Kappelmann
 import Mathlib.Algebra.ContinuedFractions.Computation.CorrectnessTerminating
 import Mathlib.Data.Nat.Fib.Basic
 import Mathlib.Tactic.Monotonicity
+import Mathlib.Algebra.GroupPower.Order
 import Std.Tactic.SolveByElim
 
 #align_import algebra.continued_fractions.computation.approximations from "leanprover-community/mathlib"@"a7e36e48519ab281320c4d192da6a7b348ce40ad"

See Zulip thread for the discussion.

@@ -434,10 +434,10 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
         · simp [n_eq_zero, le_refl]
         · exact Or.inr not_terminated_at_pred_n
       fib_le_of_continuantsAux_b this
-    have zero_lt_B : 0 < B := B_ineq.trans_lt' $ cast_pos.2 $ fib_pos.2 n.succ_pos
+    have zero_lt_B : 0 < B := B_ineq.trans_lt' <| cast_pos.2 <| fib_pos.2 n.succ_pos
     have : 0 ≤ pB := (cast_nonneg _).trans pB_ineq
     have : 0 < ifp.fr :=
-      ifp_fr_ne_zero.lt_of_le' $ IntFractPair.nth_stream_fr_nonneg stream_nth_eq
+      ifp_fr_ne_zero.lt_of_le' <| IntFractPair.nth_stream_fr_nonneg stream_nth_eq
     have : pB + ifp.fr⁻¹ * B ≠ 0 := by positivity
     -- finally, let's do the rewriting
     calc
@@ -495,7 +495,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
     haveI : ¬g.TerminatedAt (n - 1) := mt (terminated_stable n.pred_le) not_terminated_at_n
     fib_le_of_continuantsAux_b <| Or.inr this
   have zero_lt_conts_b : 0 < conts.b :=
-    conts_b_ineq.trans_lt' $ mod_cast fib_pos.2 n.succ_pos
+    conts_b_ineq.trans_lt' <| mod_cast fib_pos.2 n.succ_pos
   -- `denom'` is positive, so we can remove `|⬝|` from our goal
   suffices 1 / denom' ≤ 1 / denom by
     have : |(-1) ^ n / denom'| = 1 / denom' := by
@@ -518,7 +518,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
   suffices 0 < denom ∧ denom ≤ denom' from div_le_div_of_le_left zero_le_one this.left this.right
   constructor
   · have : 0 < pred_conts.b + gp.b * conts.b :=
-      nextConts_b_ineq.trans_lt' $ mod_cast fib_pos.2 $ succ_pos _
+      nextConts_b_ineq.trans_lt' <| mod_cast fib_pos.2 <| succ_pos _
     solve_by_elim [mul_pos]
   · -- we can cancel multiplication by `conts.b` and addition with `pred_conts.b`
     suffices : gp.b * conts.b ≤ ifp_n.fr⁻¹ * conts.b

This is quite a substantial bump as Nondet / backtrack / solve_by_elim have all moved to Std.

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

@@ -6,7 +6,7 @@ Authors: Kevin Kappelmann
 import Mathlib.Algebra.ContinuedFractions.Computation.CorrectnessTerminating
 import Mathlib.Data.Nat.Fib.Basic
 import Mathlib.Tactic.Monotonicity
-import Mathlib.Tactic.SolveByElim
+import Std.Tactic.SolveByElim
 
 #align_import algebra.continued_fractions.computation.approximations from "leanprover-community/mathlib"@"a7e36e48519ab281320c4d192da6a7b348ce40ad"
 

This converts usages of the pattern

cases h
case inl h' => ...
case inr h' => ...

which derive from mathported code, to the "structured cases" syntax:

cases h with
| inl h' => ...
| inr h' => ...

The case where the subgoals are handled with · instead of case is more contentious (and much more numerous) so I left those alone. This pattern also appears with cases', induction, induction', and rcases. Furthermore, there is a similar transformation for by_cases:

by_cases h : cond
case pos => ...
case neg => ...

is replaced by:

if h : cond then
  ...
else
  ...

Co-authored-by: Mario Carneiro <di.gama@gmail.com>

@@ -68,12 +68,12 @@ of great interest for the end user.
 /-- Shows that the fractional parts of the stream are in `[0,1)`. -/
 theorem nth_stream_fr_nonneg_lt_one {ifp_n : IntFractPair K}
     (nth_stream_eq : IntFractPair.stream v n = some ifp_n) : 0 ≤ ifp_n.fr ∧ ifp_n.fr < 1 := by
-  cases n
-  case zero =>
+  cases n with
+  | zero =>
     have : IntFractPair.of v = ifp_n := by injection nth_stream_eq
     rw [← this, IntFractPair.of]
     exact ⟨fract_nonneg _, fract_lt_one _⟩
-  case succ =>
+  | succ =>
     rcases succ_nth_stream_eq_some_iff.1 nth_stream_eq with ⟨_, _, _, ifp_of_eq_ifp_n⟩
     rw [← ifp_of_eq_ifp_n, IntFractPair.of]
     exact ⟨fract_nonneg _, fract_lt_one _⟩
@@ -238,9 +238,9 @@ theorem succ_nth_fib_le_of_nth_denom (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n -
     (fib (n + 1) : K) ≤ (of v).denominators n := by
   rw [denom_eq_conts_b, nth_cont_eq_succ_nth_cont_aux]
   have : n + 1 ≤ 1 ∨ ¬(of v).TerminatedAt (n - 1) := by
-    cases' n with n
-    case zero => exact Or.inl <| le_refl 1
-    case succ => exact Or.inr (Or.resolve_left hyp n.succ_ne_zero)
+    cases n with
+    | zero => exact Or.inl <| le_refl 1
+    | succ n => exact Or.inr (Or.resolve_left hyp n.succ_ne_zero)
   exact fib_le_of_continuantsAux_b this
 #align generalized_continued_fraction.succ_nth_fib_le_of_nth_denom GeneralizedContinuedFraction.succ_nth_fib_le_of_nth_denom
 
@@ -249,9 +249,9 @@ theorem succ_nth_fib_le_of_nth_denom (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n -
 
 theorem zero_le_of_continuantsAux_b : 0 ≤ ((of v).continuantsAux n).b := by
   let g := of v
-  induction' n with n IH
-  case zero => rfl
-  case succ =>
+  induction n with
+  | zero => rfl
+  | succ n IH =>
     cases' Decidable.em <| g.TerminatedAt (n - 1) with terminated not_terminated
     · -- terminating case
       cases' n with n
@@ -320,9 +320,9 @@ Next we prove the so-called *determinant formula* for `GeneralizedContinuedFract
 theorem determinant_aux (hyp : n = 0 ∨ ¬(of v).TerminatedAt (n - 1)) :
     ((of v).continuantsAux n).a * ((of v).continuantsAux (n + 1)).b -
       ((of v).continuantsAux n).b * ((of v).continuantsAux (n + 1)).a = (-1) ^ n := by
-  induction' n with n IH
-  case zero => simp [continuantsAux]
-  case succ =>
+  induction n with
+  | zero => simp [continuantsAux]
+  | succ n IH =>
     -- set up some shorthand notation
     let g := of v
     let conts := continuantsAux g (n + 2)

This was postponed to after the Zeckendorf PR.

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Kappelmann
 -/
 import Mathlib.Algebra.ContinuedFractions.Computation.CorrectnessTerminating
-import Mathlib.Data.Nat.Fib
+import Mathlib.Data.Nat.Fib.Basic
 import Mathlib.Tactic.Monotonicity
 import Mathlib.Tactic.SolveByElim
 

We still have the exact_mod_cast tactic, used in a few places, which somehow (?) works a little bit harder to prevent the expected type influencing the elaboration of the term. I would like to get to the bottom of this, and it will be easier once the only usages of exact_mod_cast are the ones that don't work using the term elaborator by itself.

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

@@ -143,7 +143,7 @@ theorem of_one_le_get?_part_denom {b : K}
     ∃ ifp, IntFractPair.stream v (n + 1) = some ifp ∧ (ifp.b : K) = gp_n.b
   exact IntFractPair.exists_succ_get?_stream_of_gcf_of_get?_eq_some nth_s_eq
   rw [← ifp_n_b_eq_gp_n_b]
-  exact_mod_cast IntFractPair.one_le_succ_nth_stream_b succ_nth_stream_eq
+  exact mod_cast IntFractPair.one_le_succ_nth_stream_b succ_nth_stream_eq
 #align generalized_continued_fraction.of_one_le_nth_part_denom GeneralizedContinuedFraction.of_one_le_get?_part_denom
 
 /--
@@ -225,7 +225,7 @@ theorem fib_le_of_continuantsAux_b :
         suffices 1 * (fib (n + 1) : K) ≤ gp.b * pconts.b by rwa [one_mul] at this
         have one_le_gp_b : (1 : K) ≤ gp.b :=
           of_one_le_get?_part_denom (part_denom_eq_s_b s_ppred_nth_eq)
-        have : (0 : K) ≤ fib (n + 1) := by exact_mod_cast (fib (n + 1)).zero_le
+        have : (0 : K) ≤ fib (n + 1) := mod_cast (fib (n + 1)).zero_le
         have : (0 : K) ≤ gp.b := le_trans zero_le_one one_le_gp_b
         mono
         · norm_num
@@ -261,7 +261,7 @@ theorem zero_le_of_continuantsAux_b : 0 ≤ ((of v).continuantsAux n).b := by
         simp only [this, IH]
     · -- non-terminating case
       calc
-        (0 : K) ≤ fib (n + 1) := by exact_mod_cast (n + 1).fib.zero_le
+        (0 : K) ≤ fib (n + 1) := mod_cast (n + 1).fib.zero_le
         _ ≤ ((of v).continuantsAux (n + 1)).b := fib_le_of_continuantsAux_b (Or.inr not_terminated)
 #align generalized_continued_fraction.zero_le_of_continuants_aux_b GeneralizedContinuedFraction.zero_le_of_continuantsAux_b
 
@@ -495,7 +495,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
     haveI : ¬g.TerminatedAt (n - 1) := mt (terminated_stable n.pred_le) not_terminated_at_n
     fib_le_of_continuantsAux_b <| Or.inr this
   have zero_lt_conts_b : 0 < conts.b :=
-    conts_b_ineq.trans_lt' $ by exact_mod_cast fib_pos.2 n.succ_pos
+    conts_b_ineq.trans_lt' $ mod_cast fib_pos.2 n.succ_pos
   -- `denom'` is positive, so we can remove `|⬝|` from our goal
   suffices 1 / denom' ≤ 1 / denom by
     have : |(-1) ^ n / denom'| = 1 / denom' := by
@@ -506,7 +506,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
             haveI : ¬g.TerminatedAt (n - 2) :=
               mt (terminated_stable (n.sub_le 2)) not_terminated_at_n
             fib_le_of_continuantsAux_b <| Or.inr this
-          le_trans (by exact_mod_cast (fib n).zero_le) this
+          le_trans (mod_cast (fib n).zero_le) this
         have : 0 < ifp_n.fr⁻¹ :=
           haveI zero_le_ifp_n_fract : 0 ≤ ifp_n.fr :=
             IntFractPair.nth_stream_fr_nonneg stream_nth_eq
@@ -518,7 +518,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
   suffices 0 < denom ∧ denom ≤ denom' from div_le_div_of_le_left zero_le_one this.left this.right
   constructor
   · have : 0 < pred_conts.b + gp.b * conts.b :=
-      nextConts_b_ineq.trans_lt' $ by exact_mod_cast fib_pos.2 $ succ_pos _
+      nextConts_b_ineq.trans_lt' $ mod_cast fib_pos.2 $ succ_pos _
     solve_by_elim [mul_pos]
   · -- we can cancel multiplication by `conts.b` and addition with `pred_conts.b`
     suffices : gp.b * conts.b ≤ ifp_n.fr⁻¹ * conts.b

Prove Zeckendorf's theorem: Every natural number can be written uniquely as a sum of distinct non-consecutive Fibonacci numbers.

Instead of proving an ExistsUnique statement, I define an equivalence between natural numbers and Zeckendorf representations.

Co-authored-by: Ruben Van de Velde <65514131+Ruben-VandeVelde@users.noreply.github.com>

@@ -390,7 +390,7 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
   have g_finite_correctness :
     v = GeneralizedContinuedFraction.compExactValue pred_conts conts ifp.fr :=
     compExactValue_correctness_of_stream_eq_some stream_nth_eq
-  cases' Decidable.em (ifp.fr = 0) with ifp_fr_eq_zero ifp_fr_ne_zero
+  obtain (ifp_fr_eq_zero | ifp_fr_ne_zero) := eq_or_ne ifp.fr 0
   · suffices v - g.convergents n = 0 by simpa [ifp_fr_eq_zero]
     replace g_finite_correctness : v = g.convergents n;
     · simpa [GeneralizedContinuedFraction.compExactValue, ifp_fr_eq_zero] using g_finite_correctness
@@ -434,28 +434,16 @@ theorem sub_convergents_eq {ifp : IntFractPair K}
         · simp [n_eq_zero, le_refl]
         · exact Or.inr not_terminated_at_pred_n
       fib_le_of_continuantsAux_b this
-    have zero_lt_B : 0 < B :=
-      haveI : 1 ≤ B := le_trans
-        (by exact_mod_cast fib_pos (lt_of_le_of_ne n.succ.zero_le n.succ_ne_zero.symm)) B_ineq
-      lt_of_lt_of_le zero_lt_one this
-    have zero_ne_B : 0 ≠ B := ne_of_lt zero_lt_B
-    have : 0 ≠ pB + ifp.fr⁻¹ * B := by
-      have : (0 : K) ≤ fib n := by exact_mod_cast (fib n).zero_le
-      -- 0 ≤ fib n ≤ pB
-      have zero_le_pB : 0 ≤ pB := le_trans this pB_ineq
-      have : 0 < ifp.fr⁻¹ := by
-        suffices 0 < ifp.fr by rwa [inv_pos]
-        have : 0 ≤ ifp.fr := IntFractPair.nth_stream_fr_nonneg stream_nth_eq
-        change ifp.fr ≠ 0 at ifp_fr_ne_zero
-        exact lt_of_le_of_ne this ifp_fr_ne_zero.symm
-      have : 0 < ifp.fr⁻¹ * B := mul_pos this zero_lt_B
-      have : 0 < pB + ifp.fr⁻¹ * B := add_pos_of_nonneg_of_pos zero_le_pB this
-      exact ne_of_lt this
+    have zero_lt_B : 0 < B := B_ineq.trans_lt' $ cast_pos.2 $ fib_pos.2 n.succ_pos
+    have : 0 ≤ pB := (cast_nonneg _).trans pB_ineq
+    have : 0 < ifp.fr :=
+      ifp_fr_ne_zero.lt_of_le' $ IntFractPair.nth_stream_fr_nonneg stream_nth_eq
+    have : pB + ifp.fr⁻¹ * B ≠ 0 := by positivity
     -- finally, let's do the rewriting
     calc
       (pA + ifp.fr⁻¹ * A) / (pB + ifp.fr⁻¹ * B) - A / B =
           ((pA + ifp.fr⁻¹ * A) * B - (pB + ifp.fr⁻¹ * B) * A) / ((pB + ifp.fr⁻¹ * B) * B) := by
-        rw [div_sub_div _ _ this.symm zero_ne_B.symm]
+        rw [div_sub_div _ _ this zero_lt_B.ne']
       _ = (pA * B + ifp.fr⁻¹ * A * B - (pB * A + ifp.fr⁻¹ * B * A)) / _ := by repeat' rw [add_mul]
       _ = (pA * B - pB * A) / ((pB + ifp.fr⁻¹ * B) * B) := by ring
       _ = (-1) ^ n / ((pB + ifp.fr⁻¹ * B) * B) := by rw [determinant_eq]
@@ -507,9 +495,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
     haveI : ¬g.TerminatedAt (n - 1) := mt (terminated_stable n.pred_le) not_terminated_at_n
     fib_le_of_continuantsAux_b <| Or.inr this
   have zero_lt_conts_b : 0 < conts.b :=
-    haveI : (0 : K) < fib (n + 1) := by
-      exact_mod_cast fib_pos (lt_of_le_of_ne n.succ.zero_le n.succ_ne_zero.symm)
-    lt_of_lt_of_le this conts_b_ineq
+    conts_b_ineq.trans_lt' $ by exact_mod_cast fib_pos.2 n.succ_pos
   -- `denom'` is positive, so we can remove `|⬝|` from our goal
   suffices 1 / denom' ≤ 1 / denom by
     have : |(-1) ^ n / denom'| = 1 / denom' := by
@@ -532,9 +518,7 @@ theorem abs_sub_convergents_le (not_terminated_at_n : ¬(of v).TerminatedAt n) :
   suffices 0 < denom ∧ denom ≤ denom' from div_le_div_of_le_left zero_le_one this.left this.right
   constructor
   · have : 0 < pred_conts.b + gp.b * conts.b :=
-      lt_of_lt_of_le
-        (by exact_mod_cast fib_pos (lt_of_le_of_ne n.succ.succ.zero_le n.succ.succ_ne_zero.symm))
-        nextConts_b_ineq
+      nextConts_b_ineq.trans_lt' $ by exact_mod_cast fib_pos.2 $ succ_pos _
     solve_by_elim [mul_pos]
   · -- we can cancel multiplication by `conts.b` and addition with `pred_conts.b`
     suffices : gp.b * conts.b ≤ ifp_n.fr⁻¹ * conts.b

Search&replace MulZeroClass.mul_zero -> mul_zero, MulZeroClass.zero_mul -> zero_mul.

These were introduced by Mathport, as the full name of mul_zero is actually MulZeroClass.mul_zero (it's exported with the short name).

@@ -560,7 +560,7 @@ theorem abs_sub_convergents_le' {b : K}
   -- to consider the case `(GeneralizedContinuedFraction.of v).denominators n = 0`.
   rcases (zero_le_of_denom (K := K)).eq_or_gt with
     ((hB : (GeneralizedContinuedFraction.of v).denominators n = 0) | hB)
-  · simp only [hB, MulZeroClass.mul_zero, MulZeroClass.zero_mul, div_zero, le_refl]
+  · simp only [hB, mul_zero, zero_mul, div_zero, le_refl]
   · apply one_div_le_one_div_of_le
     · have : 0 < b := zero_lt_one.trans_le (of_one_le_get?_part_denom nth_part_denom_eq)
       apply_rules [mul_pos]

We remove all possible occurences of Type _ and Sort _ in favor of Type* and Sort*.

This has nice performance benefits.

@@ -55,7 +55,7 @@ open GeneralizedContinuedFraction (of)
 
 open Int
 
-variable {K : Type _} {v : K} {n : ℕ} [LinearOrderedField K] [FloorRing K]
+variable {K : Type*} {v : K} {n : ℕ} [LinearOrderedField K] [FloorRing K]
 
 namespace IntFractPair
 

• depends on: #5966

Co-authored-by: Eric Wieser <wieser.eric@gmail.com> Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

@@ -2,17 +2,14 @@
 Copyright (c) 2020 Kevin Kappelmann. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Kevin Kappelmann
-
-! This file was ported from Lean 3 source module algebra.continued_fractions.computation.approximations
-! leanprover-community/mathlib commit a7e36e48519ab281320c4d192da6a7b348ce40ad
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.Algebra.ContinuedFractions.Computation.CorrectnessTerminating
 import Mathlib.Data.Nat.Fib
 import Mathlib.Tactic.Monotonicity
 import Mathlib.Tactic.SolveByElim
 
+#align_import algebra.continued_fractions.computation.approximations from "leanprover-community/mathlib"@"a7e36e48519ab281320c4d192da6a7b348ce40ad"
+
 /-!
 # Approximations for Continued Fraction Computations (`GeneralizedContinuedFraction.of`)
 

• depends on: https://github.com/leanprover/std4/pull/163
• depends on: #5584
• depends on: #5715
• depends on: #5729
• depends on: https://github.com/leanprover/std4/pull/173

Co-authored-by: Komyyy <pol_tta@outlook.jp> Co-authored-by: Scott Morrison <scott.morrison@gmail.com> Co-authored-by: Scott Morrison <scott.morrison@anu.edu.au> Co-authored-by: Ruben Van de Velde <65514131+Ruben-VandeVelde@users.noreply.github.com> Co-authored-by: Mario Carneiro <di.gama@gmail.com>

@@ -561,7 +561,7 @@ theorem abs_sub_convergents_le' {b : K}
   refine' (abs_sub_convergents_le not_terminated_at_n).trans _
   -- One can show that `0 < (GeneralizedContinuedFraction.of v).denominators n` but it's easier
   -- to consider the case `(GeneralizedContinuedFraction.of v).denominators n = 0`.
-  rcases zero_le_of_denom.eq_or_gt with
+  rcases (zero_le_of_denom (K := K)).eq_or_gt with
     ((hB : (GeneralizedContinuedFraction.of v).denominators n = 0) | hB)
   · simp only [hB, MulZeroClass.mul_zero, MulZeroClass.zero_mul, div_zero, le_refl]
   · apply one_div_le_one_div_of_le

Co-authored-by: int-y1 <jason_yuen2007@hotmail.com> Co-authored-by: Moritz Firsching <firsching@google.com>