algebra.continued_fractions.computation.terminates_iff_rat ⟷ Mathlib.Algebra.ContinuedFractions.Computation.TerminatesIffRat

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

@@ -201,7 +201,7 @@ theorem coe_stream_nth_rat_eq :
   induction' n with n IH
   case zero => simp [int_fract_pair.stream, coe_of_rat_eq v_eq_q]
   case succ =>
-    rw [v_eq_q] at IH 
+    rw [v_eq_q] at IH
     cases' stream_q_nth_eq : int_fract_pair.stream q n with ifp_n
     case none => simp [int_fract_pair.stream, IH.symm, v_eq_q, stream_q_nth_eq]
     case some =>
@@ -209,7 +209,7 @@ theorem coe_stream_nth_rat_eq :
       cases' Decidable.em (fr = 0) with fr_zero fr_ne_zero
       · simp [int_fract_pair.stream, IH.symm, v_eq_q, stream_q_nth_eq, fr_zero]
       · replace IH : some (int_fract_pair.mk b ↑fr) = int_fract_pair.stream (↑q) n;
-        · rwa [stream_q_nth_eq] at IH 
+        · rwa [stream_q_nth_eq] at IH
         have : (fr : K)⁻¹ = ((fr⁻¹ : ℚ) : K) := by norm_cast
         have coe_of_fr := coe_of_rat_eq this
         simpa [int_fract_pair.stream, IH.symm, v_eq_q, stream_q_nth_eq, fr_ne_zero]
@@ -367,7 +367,7 @@ theorem exists_nth_stream_eq_none_of_rat (q : ℚ) : ∃ n : ℕ, IntFractPair.s
       by
       have : 0 ≤ fract_q_num := rat.num_nonneg_iff_zero_le.elim_right (Int.fract_nonneg q)
       simp [Int.natAbs_of_nonneg this, sub_add_eq_sub_sub_swap, sub_right_comm]
-    have : ifp.fr.num ≤ -1 := by rwa [this] at ifp_fr_num_le_q_fr_num_sub_n 
+    have : ifp.fr.num ≤ -1 := by rwa [this] at ifp_fr_num_le_q_fr_num_sub_n
     have : 0 ≤ ifp.fr := (nth_stream_fr_nonneg_lt_one stream_nth_eq).left
     have : 0 ≤ ifp.fr.num := rat.num_nonneg_iff_zero_le.elim_right this
     linarith

mathlib commit https://github.com/leanprover-community/mathlib/commit/b1abe23ae96fef89ad30d9f4362c307f72a55010

@@ -246,7 +246,7 @@ theorem coe_of_s_get?_rat_eq :
   simp only [seq.nth]
   rw [← int_fract_pair.coe_stream_rat_eq v_eq_q]
   rcases succ_nth_stream_eq : int_fract_pair.stream q (n + 1) with (_ | ⟨_, _⟩) <;>
-    simp [Stream'.map, Stream'.nth, succ_nth_stream_eq]
+    simp [Stream'.map, Stream'.get, succ_nth_stream_eq]
 #align generalized_continued_fraction.coe_of_s_nth_rat_eq GeneralizedContinuedFraction.coe_of_s_get?_rat_eq
 -/
 

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.Approximations
-import Mathbin.Algebra.ContinuedFractions.Computation.CorrectnessTerminating
-import Mathbin.Data.Rat.Floor
+import Algebra.ContinuedFractions.Computation.Approximations
+import Algebra.ContinuedFractions.Computation.CorrectnessTerminating
+import Data.Rat.Floor
 
 #align_import algebra.continued_fractions.computation.terminates_iff_rat from "leanprover-community/mathlib"@"e160cefedc932ce41c7049bf0c4b0f061d06216e"
 

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.terminates_iff_rat
-! leanprover-community/mathlib commit e160cefedc932ce41c7049bf0c4b0f061d06216e
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Algebra.ContinuedFractions.Computation.Approximations
 import Mathbin.Algebra.ContinuedFractions.Computation.CorrectnessTerminating
 import Mathbin.Data.Rat.Floor
 
+#align_import algebra.continued_fractions.computation.terminates_iff_rat from "leanprover-community/mathlib"@"e160cefedc932ce41c7049bf0c4b0f061d06216e"
+
 /-!
 # Termination of Continued Fraction Computations (`gcf.of`)
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/0723536a0522d24fc2f159a096fb3304bef77472

@@ -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.terminates_iff_rat
-! leanprover-community/mathlib commit a7e36e48519ab281320c4d192da6a7b348ce40ad
+! leanprover-community/mathlib commit e160cefedc932ce41c7049bf0c4b0f061d06216e
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -15,6 +15,9 @@ import Mathbin.Data.Rat.Floor
 /-!
 # Termination of Continued Fraction Computations (`gcf.of`)
 
+> THIS FILE IS SYNCHRONIZED WITH MATHLIB4.
+> Any changes to this file require a corresponding PR to mathlib4.
+
 ## Summary
 We show that the continued fraction for a value `v`, as defined in
 `algebra.continued_fractions.computation.basic`, terminates if and only if `v` corresponds to a

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

@@ -63,6 +63,7 @@ show that `v = ↑q`.
 
 variable (v : K) (n : ℕ)
 
+#print GeneralizedContinuedFraction.exists_gcf_pair_rat_eq_of_nth_conts_aux /-
 theorem exists_gcf_pair_rat_eq_of_nth_conts_aux :
     ∃ conts : Pair ℚ, (of v).continuantsAux n = (conts.map coe : Pair K) :=
   Nat.strong_induction_on n
@@ -101,26 +102,34 @@ theorem exists_gcf_pair_rat_eq_of_nth_conts_aux :
           cases ppred_conts; cases pred_conts
           simp [next_continuants, next_numerator, next_denominator])
 #align generalized_continued_fraction.exists_gcf_pair_rat_eq_of_nth_conts_aux GeneralizedContinuedFraction.exists_gcf_pair_rat_eq_of_nth_conts_aux
+-/
 
+#print GeneralizedContinuedFraction.exists_gcf_pair_rat_eq_nth_conts /-
 theorem exists_gcf_pair_rat_eq_nth_conts :
     ∃ conts : Pair ℚ, (of v).continuants n = (conts.map coe : Pair K) := by
   rw [nth_cont_eq_succ_nth_cont_aux]; exact exists_gcf_pair_rat_eq_of_nth_conts_aux v <| n + 1
 #align generalized_continued_fraction.exists_gcf_pair_rat_eq_nth_conts GeneralizedContinuedFraction.exists_gcf_pair_rat_eq_nth_conts
+-/
 
+#print GeneralizedContinuedFraction.exists_rat_eq_nth_numerator /-
 theorem exists_rat_eq_nth_numerator : ∃ q : ℚ, (of v).numerators n = (q : K) :=
   by
   rcases exists_gcf_pair_rat_eq_nth_conts v n with ⟨⟨a, _⟩, nth_cont_eq⟩
   use a
   simp [num_eq_conts_a, nth_cont_eq]
 #align generalized_continued_fraction.exists_rat_eq_nth_numerator GeneralizedContinuedFraction.exists_rat_eq_nth_numerator
+-/
 
+#print GeneralizedContinuedFraction.exists_rat_eq_nth_denominator /-
 theorem exists_rat_eq_nth_denominator : ∃ q : ℚ, (of v).denominators n = (q : K) :=
   by
   rcases exists_gcf_pair_rat_eq_nth_conts v n with ⟨⟨_, b⟩, nth_cont_eq⟩
   use b
   simp [denom_eq_conts_b, nth_cont_eq]
 #align generalized_continued_fraction.exists_rat_eq_nth_denominator GeneralizedContinuedFraction.exists_rat_eq_nth_denominator
+-/
 
+#print GeneralizedContinuedFraction.exists_rat_eq_nth_convergent /-
 /-- Every finite convergent corresponds to a rational number. -/
 theorem exists_rat_eq_nth_convergent : ∃ q : ℚ, (of v).convergents n = (q : K) :=
   by
@@ -129,9 +138,11 @@ theorem exists_rat_eq_nth_convergent : ∃ q : ℚ, (of v).convergents n = (q :
   use Aₙ / Bₙ
   simp [nth_num_eq, nth_denom_eq, convergent_eq_num_div_denom]
 #align generalized_continued_fraction.exists_rat_eq_nth_convergent GeneralizedContinuedFraction.exists_rat_eq_nth_convergent
+-/
 
 variable {v}
 
+#print GeneralizedContinuedFraction.exists_rat_eq_of_terminates /-
 /-- Every terminating continued fraction corresponds to a rational number. -/
 theorem exists_rat_eq_of_terminates (terminates : (of v).Terminates) : ∃ q : ℚ, v = ↑q :=
   by
@@ -142,6 +153,7 @@ theorem exists_rat_eq_of_terminates (terminates : (of v).Terminates) : ∃ q : 
   have : v = (↑q : K) := Eq.trans v_eq_conv conv_eq_q
   use q, this
 #align generalized_continued_fraction.exists_rat_eq_of_terminates GeneralizedContinuedFraction.exists_rat_eq_of_terminates
+-/
 
 end RatOfTerminates
 
@@ -175,10 +187,13 @@ variable {v : K} {q : ℚ} (v_eq_q : v = (↑q : K)) (n : ℕ)
 
 namespace IntFractPair
 
+#print GeneralizedContinuedFraction.IntFractPair.coe_of_rat_eq /-
 theorem coe_of_rat_eq : ((IntFractPair.of q).mapFr coe : IntFractPair K) = IntFractPair.of v := by
   simp [int_fract_pair.of, v_eq_q]
 #align generalized_continued_fraction.int_fract_pair.coe_of_rat_eq GeneralizedContinuedFraction.IntFractPair.coe_of_rat_eq
+-/
 
+#print GeneralizedContinuedFraction.IntFractPair.coe_stream_nth_rat_eq /-
 theorem coe_stream_nth_rat_eq :
     ((IntFractPair.stream q n).map (mapFr coe) : Option <| IntFractPair K) =
       IntFractPair.stream v n :=
@@ -199,25 +214,31 @@ theorem coe_stream_nth_rat_eq :
         have coe_of_fr := coe_of_rat_eq this
         simpa [int_fract_pair.stream, IH.symm, v_eq_q, stream_q_nth_eq, fr_ne_zero]
 #align generalized_continued_fraction.int_fract_pair.coe_stream_nth_rat_eq GeneralizedContinuedFraction.IntFractPair.coe_stream_nth_rat_eq
+-/
 
+#print GeneralizedContinuedFraction.IntFractPair.coe_stream'_rat_eq /-
 theorem coe_stream'_rat_eq :
     ((IntFractPair.stream q).map (Option.map (mapFr coe)) : Stream' <| Option <| IntFractPair K) =
       IntFractPair.stream v :=
   by funext n; exact int_fract_pair.coe_stream_nth_rat_eq v_eq_q n
 #align generalized_continued_fraction.int_fract_pair.coe_stream_rat_eq GeneralizedContinuedFraction.IntFractPair.coe_stream'_rat_eq
+-/
 
 end IntFractPair
 
 /-! Now we lift the coercion results to the continued fraction computation. -/
 
 
+#print GeneralizedContinuedFraction.coe_of_h_rat_eq /-
 theorem coe_of_h_rat_eq : (↑((of q).h : ℚ) : K) = (of v).h :=
   by
   unfold of int_fract_pair.seq1
   rw [← int_fract_pair.coe_of_rat_eq v_eq_q]
   simp
 #align generalized_continued_fraction.coe_of_h_rat_eq GeneralizedContinuedFraction.coe_of_h_rat_eq
+-/
 
+#print GeneralizedContinuedFraction.coe_of_s_get?_rat_eq /-
 theorem coe_of_s_get?_rat_eq :
     (((of q).s.get? n).map (Pair.map coe) : Option <| Pair K) = (of v).s.get? n :=
   by
@@ -227,11 +248,15 @@ theorem coe_of_s_get?_rat_eq :
   rcases succ_nth_stream_eq : int_fract_pair.stream q (n + 1) with (_ | ⟨_, _⟩) <;>
     simp [Stream'.map, Stream'.nth, succ_nth_stream_eq]
 #align generalized_continued_fraction.coe_of_s_nth_rat_eq GeneralizedContinuedFraction.coe_of_s_get?_rat_eq
+-/
 
+#print GeneralizedContinuedFraction.coe_of_s_rat_eq /-
 theorem coe_of_s_rat_eq : ((of q).s.map (Pair.map coe) : Seq <| Pair K) = (of v).s := by ext n;
   rw [← coe_of_s_nth_rat_eq v_eq_q]; rfl
 #align generalized_continued_fraction.coe_of_s_rat_eq GeneralizedContinuedFraction.coe_of_s_rat_eq
+-/
 
+#print GeneralizedContinuedFraction.coe_of_rat_eq /-
 /-- Given `(v : K), (q : ℚ), and v = q`, we have that `gcf.of q = gcf.of v` -/
 theorem coe_of_rat_eq :
     (⟨(of q).h, (of q).s.map (Pair.map coe)⟩ : GeneralizedContinuedFraction K) = of v :=
@@ -240,7 +265,9 @@ theorem coe_of_rat_eq :
   obtain rfl : ↑⌊↑q⌋ = h := by injection gcf_v_eq
   simp [coe_of_h_rat_eq rfl, coe_of_s_rat_eq rfl, gcf_v_eq]
 #align generalized_continued_fraction.coe_of_rat_eq GeneralizedContinuedFraction.coe_of_rat_eq
+-/
 
+#print GeneralizedContinuedFraction.of_terminates_iff_of_rat_terminates /-
 theorem of_terminates_iff_of_rat_terminates {v : K} {q : ℚ} (v_eq_q : v = (q : K)) :
     (of v).Terminates ↔ (of q).Terminates := by
   constructor <;> intro h <;> cases' h with n h <;> use n <;>
@@ -248,6 +275,7 @@ theorem of_terminates_iff_of_rat_terminates {v : K} {q : ℚ} (v_eq_q : v = (q :
       cases (of q).s.get? n <;>
     trivial
 #align generalized_continued_fraction.of_terminates_iff_of_rat_terminates GeneralizedContinuedFraction.of_terminates_iff_of_rat_terminates
+-/
 
 end RatTranslation
 
@@ -270,13 +298,16 @@ namespace IntFractPair
 
 variable {q : ℚ} {n : ℕ}
 
+#print GeneralizedContinuedFraction.IntFractPair.of_inv_fr_num_lt_num_of_pos /-
 /-- Shows that for any `q : ℚ` with `0 < q < 1`, the numerator of the fractional part of
 `int_fract_pair.of q⁻¹` is smaller than the numerator of `q`.
 -/
 theorem of_inv_fr_num_lt_num_of_pos (q_pos : 0 < q) : (IntFractPair.of q⁻¹).fr.num < q.num :=
   Rat.fract_inv_num_lt_num_of_pos q_pos
 #align generalized_continued_fraction.int_fract_pair.of_inv_fr_num_lt_num_of_pos GeneralizedContinuedFraction.IntFractPair.of_inv_fr_num_lt_num_of_pos
+-/
 
+#print GeneralizedContinuedFraction.IntFractPair.stream_succ_nth_fr_num_lt_nth_fr_num_rat /-
 /-- Shows that the sequence of numerators of the fractional parts of the stream is strictly
 antitone. -/
 theorem stream_succ_nth_fr_num_lt_nth_fr_num_rat {ifp_n ifp_succ_n : IntFractPair ℚ}
@@ -296,7 +327,9 @@ theorem stream_succ_nth_fr_num_lt_nth_fr_num_rat {ifp_n ifp_succ_n : IntFractPai
   have : 0 < ifp_n.fr := lt_of_le_of_ne zero_le_ifp_n_fract <| ifp_n_fract_ne_zero.symm
   exact of_inv_fr_num_lt_num_of_pos this
 #align generalized_continued_fraction.int_fract_pair.stream_succ_nth_fr_num_lt_nth_fr_num_rat GeneralizedContinuedFraction.IntFractPair.stream_succ_nth_fr_num_lt_nth_fr_num_rat
+-/
 
+#print GeneralizedContinuedFraction.IntFractPair.stream_nth_fr_num_le_fr_num_sub_n_rat /-
 theorem stream_nth_fr_num_le_fr_num_sub_n_rat :
     ∀ {ifp_n : IntFractPair ℚ},
       IntFractPair.stream q n = some ifp_n → ifp_n.fr.num ≤ (IntFractPair.of q).fr.num - n :=
@@ -318,7 +351,9 @@ theorem stream_nth_fr_num_le_fr_num_sub_n_rat :
     have : ifp_succ_n.fr.num + 1 ≤ ifp_n.fr.num := Int.add_one_le_of_lt this
     exact le_trans this (IH stream_nth_eq)
 #align generalized_continued_fraction.int_fract_pair.stream_nth_fr_num_le_fr_num_sub_n_rat GeneralizedContinuedFraction.IntFractPair.stream_nth_fr_num_le_fr_num_sub_n_rat
+-/
 
+#print GeneralizedContinuedFraction.IntFractPair.exists_nth_stream_eq_none_of_rat /-
 theorem exists_nth_stream_eq_none_of_rat (q : ℚ) : ∃ n : ℕ, IntFractPair.stream q n = none :=
   by
   let fract_q_num := (Int.fract q).num; let n := fract_q_num.nat_abs + 1
@@ -337,9 +372,11 @@ theorem exists_nth_stream_eq_none_of_rat (q : ℚ) : ∃ n : ℕ, IntFractPair.s
     have : 0 ≤ ifp.fr.num := rat.num_nonneg_iff_zero_le.elim_right this
     linarith
 #align generalized_continued_fraction.int_fract_pair.exists_nth_stream_eq_none_of_rat GeneralizedContinuedFraction.IntFractPair.exists_nth_stream_eq_none_of_rat
+-/
 
 end IntFractPair
 
+#print GeneralizedContinuedFraction.terminates_of_rat /-
 /-- The continued fraction of a rational number terminates. -/
 theorem terminates_of_rat (q : ℚ) : (of q).Terminates :=
   Exists.elim (IntFractPair.exists_nth_stream_eq_none_of_rat q) fun n stream_nth_eq_none =>
@@ -347,9 +384,11 @@ theorem terminates_of_rat (q : ℚ) : (of q).Terminates :=
       (have : IntFractPair.stream q (n + 1) = none := IntFractPair.stream_isSeq q stream_nth_eq_none
       of_terminatedAt_n_iff_succ_nth_intFractPair_stream_eq_none.right this)
 #align generalized_continued_fraction.terminates_of_rat GeneralizedContinuedFraction.terminates_of_rat
+-/
 
 end TerminatesOfRat
 
+#print GeneralizedContinuedFraction.terminates_iff_rat /-
 /-- The continued fraction `generalized_continued_fraction.of v` terminates if and only if `v ∈ ℚ`.
 -/
 theorem terminates_iff_rat (v : K) : (of v).Terminates ↔ ∃ q : ℚ, v = (q : K) :=
@@ -361,6 +400,7 @@ theorem terminates_iff_rat (v : K) : (of v).Terminates ↔ ∃ q : ℚ, v = (q :
       have : (of q).Terminates := terminates_of_rat q
       (of_terminates_iff_of_rat_terminates v_eq_q).right this
 #align generalized_continued_fraction.terminates_iff_rat GeneralizedContinuedFraction.terminates_iff_rat
+-/
 
 end GeneralizedContinuedFraction
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/9fb8964792b4237dac6200193a0d533f1b3f7423

@@ -169,8 +169,6 @@ the computation first and then lift the results step-by-step.
 -- The lifting works for arbitrary linear ordered fields with a floor function.
 variable {v : K} {q : ℚ} (v_eq_q : v = (↑q : K)) (n : ℕ)
 
-include v_eq_q
-
 /-! First, we show the correspondence for the very basic functions in
 `generalized_continued_fraction.int_fract_pair`. -/
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/5f25c089cb34db4db112556f23c50d12da81b297

@@ -36,7 +36,7 @@ rational, continued fraction, termination
 
 namespace GeneralizedContinuedFraction
 
-/- ./././Mathport/Syntax/Translate/Command.lean:229:11: unsupported: unusual advanced open style -/
+/- ./././Mathport/Syntax/Translate/Command.lean:230:11: unsupported: unusual advanced open style -/
 open GeneralizedContinuedFraction (of)
 
 variable {K : Type _} [LinearOrderedField K] [FloorRing K]
@@ -90,8 +90,8 @@ theorem exists_gcf_pair_rat_eq_of_nth_conts_aux :
           simp only [this, pred_conts_eq]
         -- option.some
         · -- invoke the IH a second time
-          cases' IH n <| lt_of_le_of_lt n.le_succ <| lt_add_one <| n + 1 with
-            ppred_conts ppred_conts_eq
+          cases' IH n <| lt_of_le_of_lt n.le_succ <| lt_add_one <| n + 1 with ppred_conts
+            ppred_conts_eq
           obtain ⟨a_eq_one, z, b_eq_z⟩ : gp_n.a = 1 ∧ ∃ z : ℤ, gp_n.b = (z : K);
           exact of_part_num_eq_one_and_exists_int_part_denom_eq s_ppred_nth_eq
           -- finally, unfold the recurrence to obtain the required rational value.

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

@@ -188,7 +188,7 @@ theorem coe_stream_nth_rat_eq :
   induction' n with n IH
   case zero => simp [int_fract_pair.stream, coe_of_rat_eq v_eq_q]
   case succ =>
-    rw [v_eq_q] at IH
+    rw [v_eq_q] at IH 
     cases' stream_q_nth_eq : int_fract_pair.stream q n with ifp_n
     case none => simp [int_fract_pair.stream, IH.symm, v_eq_q, stream_q_nth_eq]
     case some =>
@@ -196,7 +196,7 @@ theorem coe_stream_nth_rat_eq :
       cases' Decidable.em (fr = 0) with fr_zero fr_ne_zero
       · simp [int_fract_pair.stream, IH.symm, v_eq_q, stream_q_nth_eq, fr_zero]
       · replace IH : some (int_fract_pair.mk b ↑fr) = int_fract_pair.stream (↑q) n;
-        · rwa [stream_q_nth_eq] at IH
+        · rwa [stream_q_nth_eq] at IH 
         have : (fr : K)⁻¹ = ((fr⁻¹ : ℚ) : K) := by norm_cast
         have coe_of_fr := coe_of_rat_eq this
         simpa [int_fract_pair.stream, IH.symm, v_eq_q, stream_q_nth_eq, fr_ne_zero]
@@ -246,7 +246,7 @@ theorem coe_of_rat_eq :
 theorem of_terminates_iff_of_rat_terminates {v : K} {q : ℚ} (v_eq_q : v = (q : K)) :
     (of v).Terminates ↔ (of q).Terminates := by
   constructor <;> intro h <;> cases' h with n h <;> use n <;>
-        simp only [seq.terminated_at, (coe_of_s_nth_rat_eq v_eq_q n).symm] at h⊢ <;>
+        simp only [seq.terminated_at, (coe_of_s_nth_rat_eq v_eq_q n).symm] at h ⊢ <;>
       cases (of q).s.get? n <;>
     trivial
 #align generalized_continued_fraction.of_terminates_iff_of_rat_terminates GeneralizedContinuedFraction.of_terminates_iff_of_rat_terminates
@@ -334,7 +334,7 @@ theorem exists_nth_stream_eq_none_of_rat (q : ℚ) : ∃ n : ℕ, IntFractPair.s
       by
       have : 0 ≤ fract_q_num := rat.num_nonneg_iff_zero_le.elim_right (Int.fract_nonneg q)
       simp [Int.natAbs_of_nonneg this, sub_add_eq_sub_sub_swap, sub_right_comm]
-    have : ifp.fr.num ≤ -1 := by rwa [this] at ifp_fr_num_le_q_fr_num_sub_n
+    have : ifp.fr.num ≤ -1 := by rwa [this] at ifp_fr_num_le_q_fr_num_sub_n 
     have : 0 ≤ ifp.fr := (nth_stream_fr_nonneg_lt_one stream_nth_eq).left
     have : 0 ≤ ifp.fr.num := rat.num_nonneg_iff_zero_le.elim_right this
     linarith

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

@@ -92,22 +92,19 @@ theorem exists_gcf_pair_rat_eq_of_nth_conts_aux :
         · -- invoke the IH a second time
           cases' IH n <| lt_of_le_of_lt n.le_succ <| lt_add_one <| n + 1 with
             ppred_conts ppred_conts_eq
-          obtain ⟨a_eq_one, z, b_eq_z⟩ : gp_n.a = 1 ∧ ∃ z : ℤ, gp_n.b = (z : K)
+          obtain ⟨a_eq_one, z, b_eq_z⟩ : gp_n.a = 1 ∧ ∃ z : ℤ, gp_n.b = (z : K);
           exact of_part_num_eq_one_and_exists_int_part_denom_eq s_ppred_nth_eq
           -- finally, unfold the recurrence to obtain the required rational value.
           simp only [a_eq_one, b_eq_z,
             continuants_aux_recurrence s_ppred_nth_eq ppred_conts_eq pred_conts_eq]
           use next_continuants 1 (z : ℚ) ppred_conts pred_conts
-          cases ppred_conts
-          cases pred_conts
+          cases ppred_conts; cases pred_conts
           simp [next_continuants, next_numerator, next_denominator])
 #align generalized_continued_fraction.exists_gcf_pair_rat_eq_of_nth_conts_aux GeneralizedContinuedFraction.exists_gcf_pair_rat_eq_of_nth_conts_aux
 
 theorem exists_gcf_pair_rat_eq_nth_conts :
-    ∃ conts : Pair ℚ, (of v).continuants n = (conts.map coe : Pair K) :=
-  by
-  rw [nth_cont_eq_succ_nth_cont_aux]
-  exact exists_gcf_pair_rat_eq_of_nth_conts_aux v <| n + 1
+    ∃ conts : Pair ℚ, (of v).continuants n = (conts.map coe : Pair K) := by
+  rw [nth_cont_eq_succ_nth_cont_aux]; exact exists_gcf_pair_rat_eq_of_nth_conts_aux v <| n + 1
 #align generalized_continued_fraction.exists_gcf_pair_rat_eq_nth_conts GeneralizedContinuedFraction.exists_gcf_pair_rat_eq_nth_conts
 
 theorem exists_rat_eq_nth_numerator : ∃ q : ℚ, (of v).numerators n = (q : K) :=
@@ -138,7 +135,7 @@ variable {v}
 /-- Every terminating continued fraction corresponds to a rational number. -/
 theorem exists_rat_eq_of_terminates (terminates : (of v).Terminates) : ∃ q : ℚ, v = ↑q :=
   by
-  obtain ⟨n, v_eq_conv⟩ : ∃ n, v = (of v).convergents n
+  obtain ⟨n, v_eq_conv⟩ : ∃ n, v = (of v).convergents n;
   exact of_correctness_of_terminates terminates
   obtain ⟨q, conv_eq_q⟩ : ∃ q : ℚ, (of v).convergents n = (↑q : K)
   exact exists_rat_eq_nth_convergent v n
@@ -198,7 +195,7 @@ theorem coe_stream_nth_rat_eq :
       cases' ifp_n with b fr
       cases' Decidable.em (fr = 0) with fr_zero fr_ne_zero
       · simp [int_fract_pair.stream, IH.symm, v_eq_q, stream_q_nth_eq, fr_zero]
-      · replace IH : some (int_fract_pair.mk b ↑fr) = int_fract_pair.stream (↑q) n
+      · replace IH : some (int_fract_pair.mk b ↑fr) = int_fract_pair.stream (↑q) n;
         · rwa [stream_q_nth_eq] at IH
         have : (fr : K)⁻¹ = ((fr⁻¹ : ℚ) : K) := by norm_cast
         have coe_of_fr := coe_of_rat_eq this
@@ -208,9 +205,7 @@ theorem coe_stream_nth_rat_eq :
 theorem coe_stream'_rat_eq :
     ((IntFractPair.stream q).map (Option.map (mapFr coe)) : Stream' <| Option <| IntFractPair K) =
       IntFractPair.stream v :=
-  by
-  funext n
-  exact int_fract_pair.coe_stream_nth_rat_eq v_eq_q n
+  by funext n; exact int_fract_pair.coe_stream_nth_rat_eq v_eq_q n
 #align generalized_continued_fraction.int_fract_pair.coe_stream_rat_eq GeneralizedContinuedFraction.IntFractPair.coe_stream'_rat_eq
 
 end IntFractPair
@@ -235,19 +230,15 @@ theorem coe_of_s_get?_rat_eq :
     simp [Stream'.map, Stream'.nth, succ_nth_stream_eq]
 #align generalized_continued_fraction.coe_of_s_nth_rat_eq GeneralizedContinuedFraction.coe_of_s_get?_rat_eq
 
-theorem coe_of_s_rat_eq : ((of q).s.map (Pair.map coe) : Seq <| Pair K) = (of v).s :=
-  by
-  ext n
-  rw [← coe_of_s_nth_rat_eq v_eq_q]
-  rfl
+theorem coe_of_s_rat_eq : ((of q).s.map (Pair.map coe) : Seq <| Pair K) = (of v).s := by ext n;
+  rw [← coe_of_s_nth_rat_eq v_eq_q]; rfl
 #align generalized_continued_fraction.coe_of_s_rat_eq GeneralizedContinuedFraction.coe_of_s_rat_eq
 
 /-- Given `(v : K), (q : ℚ), and v = q`, we have that `gcf.of q = gcf.of v` -/
 theorem coe_of_rat_eq :
     (⟨(of q).h, (of q).s.map (Pair.map coe)⟩ : GeneralizedContinuedFraction K) = of v :=
   by
-  cases' gcf_v_eq : of v with h s
-  subst v
+  cases' gcf_v_eq : of v with h s; subst v
   obtain rfl : ↑⌊↑q⌋ = h := by injection gcf_v_eq
   simp [coe_of_h_rat_eq rfl, coe_of_s_rat_eq rfl, gcf_v_eq]
 #align generalized_continued_fraction.coe_of_rat_eq GeneralizedContinuedFraction.coe_of_rat_eq
@@ -334,8 +325,7 @@ theorem exists_nth_stream_eq_none_of_rat (q : ℚ) : ∃ n : ℕ, IntFractPair.s
   by
   let fract_q_num := (Int.fract q).num; let n := fract_q_num.nat_abs + 1
   cases' stream_nth_eq : int_fract_pair.stream q n with ifp
-  · use n
-    exact stream_nth_eq
+  · use n; exact stream_nth_eq
   · -- arrive at a contradiction since the numerator decreased num + 1 times but every fractional
     -- value is nonnegative.
     have ifp_fr_num_le_q_fr_num_sub_n : ifp.fr.num ≤ fract_q_num - n :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/09079525fd01b3dda35e96adaa08d2f943e1648c

@@ -36,7 +36,7 @@ rational, continued fraction, termination
 
 namespace GeneralizedContinuedFraction
 
-/- ./././Mathport/Syntax/Translate/Command.lean:224:11: unsupported: unusual advanced open style -/
+/- ./././Mathport/Syntax/Translate/Command.lean:229:11: unsupported: unusual advanced open style -/
 open GeneralizedContinuedFraction (of)
 
 variable {K : Type _} [LinearOrderedField K] [FloorRing K]

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

@@ -225,7 +225,7 @@ theorem coe_of_h_rat_eq : (↑((of q).h : ℚ) : K) = (of v).h :=
   simp
 #align generalized_continued_fraction.coe_of_h_rat_eq GeneralizedContinuedFraction.coe_of_h_rat_eq
 
-theorem coe_of_s_nth_rat_eq :
+theorem coe_of_s_get?_rat_eq :
     (((of q).s.get? n).map (Pair.map coe) : Option <| Pair K) = (of v).s.get? n :=
   by
   simp only [of, int_fract_pair.seq1, seq.map_nth, seq.nth_tail]
@@ -233,7 +233,7 @@ theorem coe_of_s_nth_rat_eq :
   rw [← int_fract_pair.coe_stream_rat_eq v_eq_q]
   rcases succ_nth_stream_eq : int_fract_pair.stream q (n + 1) with (_ | ⟨_, _⟩) <;>
     simp [Stream'.map, Stream'.nth, succ_nth_stream_eq]
-#align generalized_continued_fraction.coe_of_s_nth_rat_eq GeneralizedContinuedFraction.coe_of_s_nth_rat_eq
+#align generalized_continued_fraction.coe_of_s_nth_rat_eq GeneralizedContinuedFraction.coe_of_s_get?_rat_eq
 
 theorem coe_of_s_rat_eq : ((of q).s.map (Pair.map coe) : Seq <| Pair K) = (of v).s :=
   by

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.terminates_iff_rat
-! leanprover-community/mathlib commit 134625f523e737f650a6ea7f0c82a6177e45e622
+! leanprover-community/mathlib commit a7e36e48519ab281320c4d192da6a7b348ce40ad
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -36,6 +36,7 @@ rational, continued fraction, termination
 
 namespace GeneralizedContinuedFraction
 
+/- ./././Mathport/Syntax/Translate/Command.lean:224:11: unsupported: unusual advanced open style -/
 open GeneralizedContinuedFraction (of)
 
 variable {K : Type _} [LinearOrderedField K] [FloorRing K]
@@ -227,14 +228,14 @@ theorem coe_of_h_rat_eq : (↑((of q).h : ℚ) : K) = (of v).h :=
 theorem coe_of_s_nth_rat_eq :
     (((of q).s.get? n).map (Pair.map coe) : Option <| Pair K) = (of v).s.get? n :=
   by
-  simp only [of, int_fract_pair.seq1, SeqCat.map_nth, SeqCat.nth_tail]
-  simp only [SeqCat.nth]
+  simp only [of, int_fract_pair.seq1, seq.map_nth, seq.nth_tail]
+  simp only [seq.nth]
   rw [← int_fract_pair.coe_stream_rat_eq v_eq_q]
   rcases succ_nth_stream_eq : int_fract_pair.stream q (n + 1) with (_ | ⟨_, _⟩) <;>
     simp [Stream'.map, Stream'.nth, succ_nth_stream_eq]
 #align generalized_continued_fraction.coe_of_s_nth_rat_eq GeneralizedContinuedFraction.coe_of_s_nth_rat_eq
 
-theorem coe_of_s_rat_eq : ((of q).s.map (Pair.map coe) : SeqCat <| Pair K) = (of v).s :=
+theorem coe_of_s_rat_eq : ((of q).s.map (Pair.map coe) : Seq <| Pair K) = (of v).s :=
   by
   ext n
   rw [← coe_of_s_nth_rat_eq v_eq_q]
@@ -254,7 +255,7 @@ theorem coe_of_rat_eq :
 theorem of_terminates_iff_of_rat_terminates {v : K} {q : ℚ} (v_eq_q : v = (q : K)) :
     (of v).Terminates ↔ (of q).Terminates := by
   constructor <;> intro h <;> cases' h with n h <;> use n <;>
-        simp only [SeqCat.TerminatedAt, (coe_of_s_nth_rat_eq v_eq_q n).symm] at h⊢ <;>
+        simp only [seq.terminated_at, (coe_of_s_nth_rat_eq v_eq_q n).symm] at h⊢ <;>
       cases (of q).s.get? n <;>
     trivial
 #align generalized_continued_fraction.of_terminates_iff_of_rat_terminates GeneralizedContinuedFraction.of_terminates_iff_of_rat_terminates

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

Reduce the diff of #11499

@@ -234,7 +234,7 @@ theorem coe_of_rat_eq :
   -- Porting note: was
   -- simp [coe_of_h_rat_eq rfl, coe_of_s_rat_eq rfl, gcf_v_eq]
   simp only [gcf_v_eq, Int.cast_inj, Rat.floor_cast, of_h_eq_floor, eq_self_iff_true,
-    Rat.cast_coe_int, and_self, coe_of_h_rat_eq rfl, coe_of_s_rat_eq rfl]
+    Rat.cast_intCast, and_self, coe_of_h_rat_eq rfl, coe_of_s_rat_eq rfl]
 #align generalized_continued_fraction.coe_of_rat_eq GeneralizedContinuedFraction.coe_of_rat_eq
 
 theorem of_terminates_iff_of_rat_terminates {v : K} {q : ℚ} (v_eq_q : v = (q : K)) :

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.

@@ -329,7 +329,7 @@ theorem exists_nth_stream_eq_none_of_rat (q : ℚ) : ∃ n : ℕ, IntFractPair.s
         sub_add_eq_sub_sub_swap, sub_right_comm, sub_self, zero_sub]
     have : 0 ≤ ifp.fr := (nth_stream_fr_nonneg_lt_one stream_nth_eq).left
     have : 0 ≤ ifp.fr.num := Rat.num_nonneg.mpr this
-    linarith
+    omega
 #align generalized_continued_fraction.int_fract_pair.exists_nth_stream_eq_none_of_rat GeneralizedContinuedFraction.IntFractPair.exists_nth_stream_eq_none_of_rat
 
 end IntFractPair

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.

@@ -89,8 +89,8 @@ nonrec theorem exists_gcf_pair_rat_eq_of_nth_conts_aux :
         · -- invoke the IH a second time
           cases' IH n <| lt_of_le_of_lt n.le_succ <| lt_add_one <| n + 1 with ppred_conts
             ppred_conts_eq
-          obtain ⟨a_eq_one, z, b_eq_z⟩ : gp_n.a = 1 ∧ ∃ z : ℤ, gp_n.b = (z : K);
-          exact of_part_num_eq_one_and_exists_int_part_denom_eq s_ppred_nth_eq
+          obtain ⟨a_eq_one, z, b_eq_z⟩ : gp_n.a = 1 ∧ ∃ z : ℤ, gp_n.b = (z : K) :=
+            of_part_num_eq_one_and_exists_int_part_denom_eq s_ppred_nth_eq
           -- finally, unfold the recurrence to obtain the required rational value.
           simp only [a_eq_one, b_eq_z,
             continuantsAux_recurrence s_ppred_nth_eq ppred_conts_eq pred_conts_eq]
@@ -128,10 +128,10 @@ variable {v}
 
 /-- Every terminating continued fraction corresponds to a rational number. -/
 theorem exists_rat_eq_of_terminates (terminates : (of v).Terminates) : ∃ q : ℚ, v = ↑q := by
-  obtain ⟨n, v_eq_conv⟩ : ∃ n, v = (of v).convergents n;
-  exact of_correctness_of_terminates terminates
-  obtain ⟨q, conv_eq_q⟩ : ∃ q : ℚ, (of v).convergents n = (↑q : K)
-  exact exists_rat_eq_nth_convergent v n
+  obtain ⟨n, v_eq_conv⟩ : ∃ n, v = (of v).convergents n :=
+    of_correctness_of_terminates terminates
+  obtain ⟨q, conv_eq_q⟩ : ∃ q : ℚ, (of v).convergents n = (↑q : K) :=
+    exists_rat_eq_nth_convergent v n
   have : v = (↑q : K) := Eq.trans v_eq_conv conv_eq_q
   use q, this
 #align generalized_continued_fraction.exists_rat_eq_of_terminates GeneralizedContinuedFraction.exists_rat_eq_of_terminates
@@ -283,8 +283,8 @@ theorem stream_succ_nth_fr_num_lt_nth_fr_num_rat {ifp_n ifp_succ_n : IntFractPai
   obtain ⟨ifp_n', stream_nth_eq', ifp_n_fract_ne_zero, IntFractPair.of_eq_ifp_succ_n⟩ :
     ∃ ifp_n',
       IntFractPair.stream q n = some ifp_n' ∧
-        ifp_n'.fr ≠ 0 ∧ IntFractPair.of ifp_n'.fr⁻¹ = ifp_succ_n
-  exact succ_nth_stream_eq_some_iff.mp stream_succ_nth_eq
+        ifp_n'.fr ≠ 0 ∧ IntFractPair.of ifp_n'.fr⁻¹ = ifp_succ_n :=
+    succ_nth_stream_eq_some_iff.mp stream_succ_nth_eq
   have : ifp_n = ifp_n' := by injection Eq.trans stream_nth_eq.symm stream_nth_eq'
   cases this
   rw [← IntFractPair.of_eq_ifp_succ_n]

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

@@ -75,7 +75,7 @@ nonrec theorem exists_gcf_pair_rat_eq_of_nth_conts_aux :
       -- n = 1
       · suffices ∃ conts : Pair ℚ, Pair.mk g.h 1 = conts.map (↑) by simpa [continuantsAux]
         use Pair.mk ⌊v⌋ 1
-        simp
+        simp [g]
       -- 2 ≤ n
       · cases' IH (n + 1) <| lt_add_one (n + 1) with pred_conts pred_conts_eq
         -- invoke the IH
@@ -325,8 +325,8 @@ theorem exists_nth_stream_eq_none_of_rat (q : ℚ) : ∃ n : ℕ, IntFractPair.s
       have : 0 ≤ fract_q_num := Rat.num_nonneg.mpr (Int.fract_nonneg q)
       -- Porting note: was
       -- simp [Int.natAbs_of_nonneg this, sub_add_eq_sub_sub_swap, sub_right_comm]
-      simp only [Nat.cast_add, Int.natAbs_of_nonneg this, Nat.cast_one, sub_add_eq_sub_sub_swap,
-        sub_right_comm, sub_self, zero_sub]
+      simp only [n, Nat.cast_add, Int.natAbs_of_nonneg this, Nat.cast_one,
+        sub_add_eq_sub_sub_swap, sub_right_comm, sub_self, zero_sub]
     have : 0 ≤ ifp.fr := (nth_stream_fr_nonneg_lt_one stream_nth_eq).left
     have : 0 ≤ ifp.fr.num := Rat.num_nonneg.mpr this
     linarith

and rename num_nonneg_iff_zero_le to num_nonneg, num_pos_iff_pos to num_pos

From LeanAPAP

@@ -322,13 +322,13 @@ theorem exists_nth_stream_eq_none_of_rat (q : ℚ) : ∃ n : ℕ, IntFractPair.s
     have ifp_fr_num_le_q_fr_num_sub_n : ifp.fr.num ≤ fract_q_num - n :=
       stream_nth_fr_num_le_fr_num_sub_n_rat stream_nth_eq
     have : fract_q_num - n = -1 := by
-      have : 0 ≤ fract_q_num := Rat.num_nonneg_iff_zero_le.mpr (Int.fract_nonneg q)
+      have : 0 ≤ fract_q_num := Rat.num_nonneg.mpr (Int.fract_nonneg q)
       -- Porting note: was
       -- simp [Int.natAbs_of_nonneg this, sub_add_eq_sub_sub_swap, sub_right_comm]
       simp only [Nat.cast_add, Int.natAbs_of_nonneg this, Nat.cast_one, sub_add_eq_sub_sub_swap,
         sub_right_comm, sub_self, zero_sub]
     have : 0 ≤ ifp.fr := (nth_stream_fr_nonneg_lt_one stream_nth_eq).left
-    have : 0 ≤ ifp.fr.num := Rat.num_nonneg_iff_zero_le.mpr this
+    have : 0 ≤ ifp.fr.num := Rat.num_nonneg.mpr this
     linarith
 #align generalized_continued_fraction.int_fract_pair.exists_nth_stream_eq_none_of_rat GeneralizedContinuedFraction.IntFractPair.exists_nth_stream_eq_none_of_rat
 

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>

@@ -188,8 +188,8 @@ theorem coe_stream_nth_rat_eq :
       cases' ifp_n with b fr
       cases' Decidable.em (fr = 0) with fr_zero fr_ne_zero
       · simp [IntFractPair.stream, IH.symm, v_eq_q, stream_q_nth_eq, fr_zero]
-      · replace IH : some (IntFractPair.mk b (fr : K)) = IntFractPair.stream (↑q) n;
-        · rwa [stream_q_nth_eq] at IH
+      · replace IH : some (IntFractPair.mk b (fr : K)) = IntFractPair.stream (↑q) n := by
+          rwa [stream_q_nth_eq] at IH
         have : (fr : K)⁻¹ = ((fr⁻¹ : ℚ) : K) := by norm_cast
         have coe_of_fr := coe_of_rat_eq this
         simpa [IntFractPair.stream, IH.symm, v_eq_q, stream_q_nth_eq, fr_ne_zero]

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>

@@ -175,16 +175,16 @@ theorem coe_of_rat_eq : ((IntFractPair.of q).mapFr (↑) : IntFractPair K) = Int
 theorem coe_stream_nth_rat_eq :
     ((IntFractPair.stream q n).map (mapFr (↑)) : Option <| IntFractPair K) =
       IntFractPair.stream v n := by
-  induction' n with n IH
-  case zero =>
+  induction n with
+  | zero =>
     -- Porting note: was
     -- simp [IntFractPair.stream, coe_of_rat_eq v_eq_q]
     simp only [IntFractPair.stream, Option.map_some', coe_of_rat_eq v_eq_q]
-  case succ =>
+  | succ n IH =>
     rw [v_eq_q] at IH
-    cases' stream_q_nth_eq : IntFractPair.stream q n with ifp_n
-    case none => simp [IntFractPair.stream, IH.symm, v_eq_q, stream_q_nth_eq]
-    case some =>
+    cases stream_q_nth_eq : IntFractPair.stream q n with
+    | none => simp [IntFractPair.stream, IH.symm, v_eq_q, stream_q_nth_eq]
+    | some ifp_n =>
       cases' ifp_n with b fr
       cases' Decidable.em (fr = 0) with fr_zero fr_ne_zero
       · simp [IntFractPair.stream, IH.symm, v_eq_q, stream_q_nth_eq, fr_zero]
@@ -296,12 +296,12 @@ theorem stream_succ_nth_fr_num_lt_nth_fr_num_rat {ifp_n ifp_succ_n : IntFractPai
 theorem stream_nth_fr_num_le_fr_num_sub_n_rat :
     ∀ {ifp_n : IntFractPair ℚ},
       IntFractPair.stream q n = some ifp_n → ifp_n.fr.num ≤ (IntFractPair.of q).fr.num - n := by
-  induction' n with n IH
-  case zero =>
+  induction n with
+  | zero =>
     intro ifp_zero stream_zero_eq
     have : IntFractPair.of q = ifp_zero := by injection stream_zero_eq
     simp [le_refl, this.symm]
-  case succ =>
+  | succ n IH =>
     intro ifp_succ_n stream_succ_nth_eq
     suffices ifp_succ_n.fr.num + 1 ≤ (IntFractPair.of q).fr.num - n by
       rw [Int.ofNat_succ, sub_add_eq_sub_sub]

Many of nth (e.g. list.nth, stream.seq.nth) are renamed to get? in Mathlib 4, but Stream'.nth had been remained as it.

@@ -218,7 +218,7 @@ theorem coe_of_s_get?_rat_eq :
   simp only [Stream'.Seq.get?]
   rw [← IntFractPair.coe_stream'_rat_eq v_eq_q]
   rcases succ_nth_stream_eq : IntFractPair.stream q (n + 1) with (_ | ⟨_, _⟩) <;>
-    simp [Stream'.map, Stream'.nth, succ_nth_stream_eq]
+    simp [Stream'.map, Stream'.get, succ_nth_stream_eq]
 #align generalized_continued_fraction.coe_of_s_nth_rat_eq GeneralizedContinuedFraction.coe_of_s_get?_rat_eq
 
 theorem coe_of_s_rat_eq : ((of q).s.map (Pair.map ((↑))) : Stream'.Seq <| Pair K) = (of v).s := by

And fix some names in comments where this revealed issues

@@ -10,16 +10,16 @@ import Mathlib.Data.Rat.Floor
 #align_import algebra.continued_fractions.computation.terminates_iff_rat from "leanprover-community/mathlib"@"a7e36e48519ab281320c4d192da6a7b348ce40ad"
 
 /-!
-# Termination of Continued Fraction Computations (`gcf.of`)
+# Termination of Continued Fraction Computations (`GeneralizedContinuedFraction.of`)
 
 ## Summary
 We show that the continued fraction for a value `v`, as defined in
-`algebra.continued_fractions.computation.basic`, terminates if and only if `v` corresponds to a
+`Mathlib.Algebra.ContinuedFractions.Basic`, terminates if and only if `v` corresponds to a
 rational number, that is `↑v = q` for some `q : ℚ`.
 
 ## Main Theorems
 
-- `generalized_continued_fraction.coe_of_rat` shows that
+- `GeneralizedContinuedFraction.coe_of_rat_eq` shows that
   `GeneralizedContinuedFraction.of v = GeneralizedContinuedFraction.of q` for `v : α` given that
   `↑v = q` and `q : ℚ`.
 - `GeneralizedContinuedFraction.terminates_iff_rat` shows that
@@ -152,7 +152,7 @@ In particular, we show that
       GeneralizedContinuedFraction K)
   = GeneralizedContinuedFraction.of v`
 ```
-in `generalized_continued_fraction.coe_of_rat`.
+in `GeneralizedContinuedFraction.coe_of_rat_eq`.
 
 To do this, we proceed bottom-up, showing the correspondence between the basic functions involved in
 the Computation first and then lift the results step-by-step.
@@ -225,7 +225,7 @@ theorem coe_of_s_rat_eq : ((of q).s.map (Pair.map ((↑))) : Stream'.Seq <| Pair
   ext n; rw [← coe_of_s_get?_rat_eq v_eq_q]; rfl
 #align generalized_continued_fraction.coe_of_s_rat_eq GeneralizedContinuedFraction.coe_of_s_rat_eq
 
-/-- Given `(v : K), (q : ℚ), and v = q`, we have that `gcf.of q = gcf.of v` -/
+/-- Given `(v : K), (q : ℚ), and v = q`, we have that `of q = of v` -/
 theorem coe_of_rat_eq :
     (⟨(of q).h, (of q).s.map (Pair.map (↑))⟩ : GeneralizedContinuedFraction K) = of v := by
   cases' gcf_v_eq : of v with h s; subst v
@@ -268,7 +268,7 @@ namespace IntFractPair
 variable {q : ℚ} {n : ℕ}
 
 /-- Shows that for any `q : ℚ` with `0 < q < 1`, the numerator of the fractional part of
-`int_fract_pair.of q⁻¹` is smaller than the numerator of `q`.
+`IntFractPair.of q⁻¹` is smaller than the numerator of `q`.
 -/
 theorem of_inv_fr_num_lt_num_of_pos (q_pos : 0 < q) : (IntFractPair.of q⁻¹).fr.num < q.num :=
   Rat.fract_inv_num_lt_num_of_pos q_pos

A linter that throws on seeing a colon at the start of a line, according to the style guideline that says these operators should go before linebreaks.

@@ -148,8 +148,8 @@ some technical translation lemmas. More precisely, in this section, we show that
 number `q : ℚ` and value `v : K` with `v = ↑q`, the continued fraction of `q` and `v` coincide.
 In particular, we show that
 ```lean
-    (↑(GeneralizedContinuedFraction.of q : GeneralizedContinuedFraction ℚ)
-      : GeneralizedContinuedFraction K)
+    (↑(GeneralizedContinuedFraction.of q : GeneralizedContinuedFraction ℚ) :
+      GeneralizedContinuedFraction K)
   = GeneralizedContinuedFraction.of v`
 ```
 in `generalized_continued_fraction.coe_of_rat`.

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

This has nice performance benefits.

@@ -36,7 +36,7 @@ namespace GeneralizedContinuedFraction
 /- ./././Mathport/Syntax/Translate/Command.lean:230:11: unsupported: unusual advanced open style -/
 open GeneralizedContinuedFraction (of)
 
-variable {K : Type _} [LinearOrderedField K] [FloorRing K]
+variable {K : Type*} [LinearOrderedField K] [FloorRing K]
 
 /-
 We will have to constantly coerce along our structures in the following proofs using their provided

Changes:

• use now by default discharges with try with_reducible use_discharger with a custom discharger tactic rather than try with_reducible rfl, which makes it be closer to exists and the use in mathlib3. It doesn't go so far as to do try with_reducible trivial since that involves the contradiction tactic.
• this discharger is configurable with use (discharger := tacticSeq...)
• the use evaluation loop will try refining after constructor failure, so it can be used to fill in all arguments rather than all but the last, like in mathlib3 (closes #5072) but with the caveat that it only works so long as the last argument is not an inductive type (like Eq).
• adds use!, which is nearly the same as the mathlib3 use and fills in constructor arguments along the nodes and leaves of the nested constructor expressions. This version tries refining before applying constructors, so it can be used like exact for the last argument.

The difference between mathlib3 use and this use! is that (1) use! uses a different tactic to discharge goals (mathlib3 used trivial', which did reducible refl, but also contradiction, which we don't emulate) (2) it does not rewrite using exists_prop. Regarding 2, this feature seems to be less useful now that bounded existentials encode the bound using a conjunction rather than with nested existentials. We do have exists_prop as part of use_discharger however.

Co-authored-by: Floris van Doorn <fpvdoorn@gmail.com>

@@ -133,8 +133,7 @@ theorem exists_rat_eq_of_terminates (terminates : (of v).Terminates) : ∃ q : 
   obtain ⟨q, conv_eq_q⟩ : ∃ q : ℚ, (of v).convergents n = (↑q : K)
   exact exists_rat_eq_nth_convergent v n
   have : v = (↑q : K) := Eq.trans v_eq_conv conv_eq_q
-  -- Porting note(https://github.com/leanprover-community/mathlib4/issues/5072): was `use`
-  exact ⟨q, this⟩
+  use q, this
 #align generalized_continued_fraction.exists_rat_eq_of_terminates GeneralizedContinuedFraction.exists_rat_eq_of_terminates
 
 end RatOfTerminates
@@ -317,7 +316,7 @@ theorem stream_nth_fr_num_le_fr_num_sub_n_rat :
 theorem exists_nth_stream_eq_none_of_rat (q : ℚ) : ∃ n : ℕ, IntFractPair.stream q n = none := by
   let fract_q_num := (Int.fract q).num; let n := fract_q_num.natAbs + 1
   cases' stream_nth_eq : IntFractPair.stream q n with ifp
-  · use n; exact stream_nth_eq
+  · use n, stream_nth_eq
   · -- arrive at a contradiction since the numerator decreased num + 1 times but every fractional
     -- value is nonnegative.
     have ifp_fr_num_le_q_fr_num_sub_n : ifp.fr.num ≤ fract_q_num - n :=

• depends on: #5966

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

@@ -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.terminates_iff_rat
-! 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.Approximations
 import Mathlib.Algebra.ContinuedFractions.Computation.CorrectnessTerminating
 import Mathlib.Data.Rat.Floor
 
+#align_import algebra.continued_fractions.computation.terminates_iff_rat from "leanprover-community/mathlib"@"a7e36e48519ab281320c4d192da6a7b348ce40ad"
+
 /-!
 # Termination of Continued Fraction Computations (`gcf.of`)