algebra.ring.ulift | Mathlib porting status

Changes since the initial port

The following section lists changes to this file in mathlib3 and mathlib4 that occured after the initial port. Most recent changes are shown first. Hovering over a commit will show all commits associated with the same mathlib3 commit.

Changes in mathlib3

13e18cfa

(last sync)

chore(algebra/ring/ulift): Split off and golf field instances (#18590)

Move field-like instances on ulift from algebra.ring.ulift to a new file algebra.field.ulift. Golf them by declaring the has_nat_cast and has_int_cast instances earlier.

Diff

@@ -4,7 +4,6 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison
 -/
 import algebra.group.ulift
-import algebra.field.defs
 import algebra.ring.equiv
 
 /-!
@@ -107,25 +106,4 @@ instance comm_ring [comm_ring α] : comm_ring (ulift α) :=
 by refine_struct { .. ulift.ring };
 tactic.pi_instance_derive_field
 
-instance [has_rat_cast α] : has_rat_cast (ulift α) :=
-⟨λ a, ulift.up (coe a)⟩
-
-@[simp] lemma rat_cast_down [has_rat_cast α] (n : ℚ) : ulift.down (n : ulift α) = n :=
-rfl
-
-instance field [field α] : field (ulift α) :=
-begin
-  have of_rat_mk : ∀ a b h1 h2, ((⟨a, b, h1, h2⟩ : ℚ) : ulift α) = ↑a * (↑b)⁻¹,
-  { intros a b h1 h2,
-    ext,
-    rw [rat_cast_down, mul_down, inv_down, nat_cast_down, int_cast_down],
-    exact field.rat_cast_mk a b h1 h2 },
-  refine_struct { zero := (0 : ulift α), inv := has_inv.inv, div := has_div.div,
-  zpow := λ n a, ulift.up (a.down ^ n), rat_cast := coe, rat_cast_mk := of_rat_mk, qsmul := (•),
-  .. @ulift.nontrivial α _, .. ulift.comm_ring }; tactic.pi_instance_derive_field,
-  -- `mul_inv_cancel` requires special attention: it leaves the goal `∀ {a}, a ≠ 0 → a * a⁻¹ = 1`.
-  cases a,
-  tauto
-end
-
 end ulift

207cfac9

(first ported)

Changes in mathlib3port

mathlib3

mathlib3port

13e18cfa

bump to nightly-2024-04-06-08

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

e34029c9

Diff

@@ -3,7 +3,7 @@ Copyright (c) 2020 Scott Morrison. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison
 -/
-import Algebra.Group.Ulift
+import Algebra.Group.ULift
 import Algebra.Ring.Equiv
 
 #align_import algebra.ring.ulift from "leanprover-community/mathlib"@"13e18cfa070ea337ea960176414f5ae3a1534aae"

13e18cfa

bump to nightly-2023-09-24-06

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

5655435f

Diff

@@ -3,8 +3,8 @@ Copyright (c) 2020 Scott Morrison. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison
 -/
-import Mathbin.Algebra.Group.Ulift
-import Mathbin.Algebra.Ring.Equiv
+import Algebra.Group.Ulift
+import Algebra.Ring.Equiv
 
 #align_import algebra.ring.ulift from "leanprover-community/mathlib"@"13e18cfa070ea337ea960176414f5ae3a1534aae"

13e18cfa

bump to nightly-2023-07-20-09

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

9c56d0dd

Diff

@@ -2,15 +2,12 @@
 Copyright (c) 2020 Scott Morrison. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison
-
-! This file was ported from Lean 3 source module algebra.ring.ulift
-! leanprover-community/mathlib commit 13e18cfa070ea337ea960176414f5ae3a1534aae
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Algebra.Group.Ulift
 import Mathbin.Algebra.Ring.Equiv
 
+#align_import algebra.ring.ulift from "leanprover-community/mathlib"@"13e18cfa070ea337ea960176414f5ae3a1534aae"
+
 /-!
 # `ulift` instances for ring

13e18cfa

bump to nightly-2023-06-13-21

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

829520ac

Diff

@@ -99,6 +99,7 @@ instance semiring [Semiring α] : Semiring (ULift α) := by
 #align ulift.semiring ULift.semiring
 -/
 
+#print ULift.ringEquiv /-
 /-- The ring equivalence between `ulift α` and `α`.
 -/
 def ringEquiv [NonUnitalNonAssocSemiring α] : ULift α ≃+* α
@@ -110,6 +111,7 @@ def ringEquiv [NonUnitalNonAssocSemiring α] : ULift α ≃+* α
   left_inv := by tidy
   right_inv := by tidy
 #align ulift.ring_equiv ULift.ringEquiv
+-/
 
 #print ULift.nonUnitalCommSemiring /-
 instance nonUnitalCommSemiring [NonUnitalCommSemiring α] : NonUnitalCommSemiring (ULift α) := by

13e18cfa

bump to nightly-2023-06-01-16

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

b9c87c70

Diff

@@ -35,7 +35,7 @@ namespace ULift
 instance mulZeroClass [MulZeroClass α] : MulZeroClass (ULift α) := by
   refine_struct
       { zero := (0 : ULift α)
-        mul := (· * ·).. } <;>
+        mul := (· * ·) .. } <;>
     pi_instance_derive_field
 #align ulift.mul_zero_class ULift.mulZeroClass
 -/
@@ -44,7 +44,7 @@ instance mulZeroClass [MulZeroClass α] : MulZeroClass (ULift α) := by
 instance distrib [Distrib α] : Distrib (ULift α) := by
   refine_struct
       { add := (· + ·)
-        mul := (· * ·).. } <;>
+        mul := (· * ·) .. } <;>
     pi_instance_derive_field
 #align ulift.distrib ULift.distrib
 -/

13e18cfa

bump to nightly-2023-05-28-06

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

ba5d8b97

Diff

@@ -99,12 +99,6 @@ instance semiring [Semiring α] : Semiring (ULift α) := by
 #align ulift.semiring ULift.semiring
 -/
 
-/- warning: ulift.ring_equiv -> ULift.ringEquiv is a dubious translation:
-lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : NonUnitalNonAssocSemiring.{u1} α], RingEquiv.{max u1 u2, u1} (ULift.{u2, u1} α) α (ULift.mul.{u1, u2} α (Distrib.toHasMul.{u1} α (NonUnitalNonAssocSemiring.toDistrib.{u1} α _inst_1))) (ULift.add.{u1, u2} α (Distrib.toHasAdd.{u1} α (NonUnitalNonAssocSemiring.toDistrib.{u1} α _inst_1))) (Distrib.toHasMul.{u1} α (NonUnitalNonAssocSemiring.toDistrib.{u1} α _inst_1)) (Distrib.toHasAdd.{u1} α (NonUnitalNonAssocSemiring.toDistrib.{u1} α _inst_1))
-but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : NonUnitalNonAssocSemiring.{u1} α], RingEquiv.{max u1 u2, u1} (ULift.{u2, u1} α) α (ULift.mul.{u1, u2} α (NonUnitalNonAssocSemiring.toMul.{u1} α _inst_1)) (NonUnitalNonAssocSemiring.toMul.{u1} α _inst_1) (ULift.add.{u1, u2} α (Distrib.toAdd.{u1} α (NonUnitalNonAssocSemiring.toDistrib.{u1} α _inst_1))) (Distrib.toAdd.{u1} α (NonUnitalNonAssocSemiring.toDistrib.{u1} α _inst_1))
-Case conversion may be inaccurate. Consider using '#align ulift.ring_equiv ULift.ringEquivₓ'. -/
 /-- The ring equivalence between `ulift α` and `α`.
 -/
 def ringEquiv [NonUnitalNonAssocSemiring α] : ULift α ≃+* α

13e18cfa

bump to nightly-2023-03-18-02

mathlib commit https://github.com/leanprover-community/mathlib/commit/02ba8949f486ebecf93fe7460f1ed0564b5e442c

24261a71

Diff

@@ -4,12 +4,11 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison
 
 ! This file was ported from Lean 3 source module algebra.ring.ulift
-! leanprover-community/mathlib commit c3291da49cfa65f0d43b094750541c0731edc932
+! leanprover-community/mathlib commit 13e18cfa070ea337ea960176414f5ae3a1534aae
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
 import Mathbin.Algebra.Group.Ulift
-import Mathbin.Algebra.Field.Defs
 import Mathbin.Algebra.Ring.Equiv
 
 /-!
@@ -225,39 +224,5 @@ instance commRing [CommRing α] : CommRing (ULift α) := by
 #align ulift.comm_ring ULift.commRing
 -/
 
-instance [HasRatCast α] : HasRatCast (ULift α) :=
-  ⟨fun a => ULift.up (coe a)⟩
-
-@[simp]
-theorem rat_cast_down [HasRatCast α] (n : ℚ) : ULift.down (n : ULift α) = n :=
-  rfl
-#align ulift.rat_cast_down ULift.rat_cast_down
-
-#print ULift.field /-
-instance field [Field α] : Field (ULift α) :=
-  by
-  have of_rat_mk : ∀ a b h1 h2, ((⟨a, b, h1, h2⟩ : ℚ) : ULift α) = ↑a * (↑b)⁻¹ :=
-    by
-    intro a b h1 h2
-    ext
-    rw [rat_cast_down, mul_down, inv_down, nat_cast_down, int_cast_down]
-    exact Field.ratCast_mk a b h1 h2
-  refine_struct
-      { @ULift.nontrivial α _,
-        ULift.commRing with
-        zero := (0 : ULift α)
-        inv := Inv.inv
-        div := Div.div
-        zpow := fun n a => ULift.up (a.down ^ n)
-        ratCast := coe
-        ratCast_mk := of_rat_mk
-        qsmul := (· • ·) } <;>
-    pi_instance_derive_field
-  -- `mul_inv_cancel` requires special attention: it leaves the goal `∀ {a}, a ≠ 0 → a * a⁻¹ = 1`.
-  cases a
-  tauto
-#align ulift.field ULift.field
--/
-
 end ULift

c3291da4

bump to nightly-2023-03-17-16

mathlib commit https://github.com/leanprover-community/mathlib/commit/da3fc4a33ff6bc75f077f691dc94c217b8d41559

624c906c

Diff

@@ -228,12 +228,6 @@ instance commRing [CommRing α] : CommRing (ULift α) := by
 instance [HasRatCast α] : HasRatCast (ULift α) :=
   ⟨fun a => ULift.up (coe a)⟩
 
-/- warning: ulift.rat_cast_down -> ULift.rat_cast_down is a dubious translation:
-lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : HasRatCast.{u1} α] (n : Rat), Eq.{succ u1} α (ULift.down.{u2, u1} α ((fun (a : Type) (b : Type.{max u1 u2}) [self : HasLiftT.{1, succ (max u1 u2)} a b] => self.0) Rat (ULift.{u2, u1} α) (HasLiftT.mk.{1, succ (max u1 u2)} Rat (ULift.{u2, u1} α) (CoeTCₓ.coe.{1, succ (max u1 u2)} Rat (ULift.{u2, u1} α) (Rat.castCoe.{max u1 u2} (ULift.{u2, u1} α) (ULift.hasRatCast.{u1, u2} α _inst_1)))) n)) ((fun (a : Type) (b : Type.{u1}) [self : HasLiftT.{1, succ u1} a b] => self.0) Rat α (HasLiftT.mk.{1, succ u1} Rat α (CoeTCₓ.coe.{1, succ u1} Rat α (Rat.castCoe.{u1} α _inst_1))) n)
-but is expected to have type
-  forall {α : Type.{u2}} [_inst_1 : RatCast.{u2} α] (n : Rat), Eq.{succ u2} α (ULift.down.{u1, u2} α (Rat.cast.{max u2 u1} (ULift.{u1, u2} α) (ULift.instRatCastULift.{u2, u1} α _inst_1) n)) (Rat.cast.{u2} α _inst_1 n)
-Case conversion may be inaccurate. Consider using '#align ulift.rat_cast_down ULift.rat_cast_downₓ'. -/
 @[simp]
 theorem rat_cast_down [HasRatCast α] (n : ℚ) : ULift.down (n : ULift α) = n :=
   rfl

c3291da4

bump to nightly-2023-03-11-22

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

a8ee822f

Diff

@@ -225,17 +225,17 @@ instance commRing [CommRing α] : CommRing (ULift α) := by
 #align ulift.comm_ring ULift.commRing
 -/
 
-instance [RatCast α] : RatCast (ULift α) :=
+instance [HasRatCast α] : HasRatCast (ULift α) :=
   ⟨fun a => ULift.up (coe a)⟩
 
 /- warning: ulift.rat_cast_down -> ULift.rat_cast_down is a dubious translation:
 lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : RatCast.{u1} α] (n : Rat), Eq.{succ u1} α (ULift.down.{u2, u1} α ((fun (a : Type) (b : Type.{max u1 u2}) [self : HasLiftT.{1, succ (max u1 u2)} a b] => self.0) Rat (ULift.{u2, u1} α) (HasLiftT.mk.{1, succ (max u1 u2)} Rat (ULift.{u2, u1} α) (CoeTCₓ.coe.{1, succ (max u1 u2)} Rat (ULift.{u2, u1} α) (Rat.castCoe.{max u1 u2} (ULift.{u2, u1} α) (ULift.hasRatCast.{u1, u2} α _inst_1)))) n)) ((fun (a : Type) (b : Type.{u1}) [self : HasLiftT.{1, succ u1} a b] => self.0) Rat α (HasLiftT.mk.{1, succ u1} Rat α (CoeTCₓ.coe.{1, succ u1} Rat α (Rat.castCoe.{u1} α _inst_1))) n)
+  forall {α : Type.{u1}} [_inst_1 : HasRatCast.{u1} α] (n : Rat), Eq.{succ u1} α (ULift.down.{u2, u1} α ((fun (a : Type) (b : Type.{max u1 u2}) [self : HasLiftT.{1, succ (max u1 u2)} a b] => self.0) Rat (ULift.{u2, u1} α) (HasLiftT.mk.{1, succ (max u1 u2)} Rat (ULift.{u2, u1} α) (CoeTCₓ.coe.{1, succ (max u1 u2)} Rat (ULift.{u2, u1} α) (Rat.castCoe.{max u1 u2} (ULift.{u2, u1} α) (ULift.hasRatCast.{u1, u2} α _inst_1)))) n)) ((fun (a : Type) (b : Type.{u1}) [self : HasLiftT.{1, succ u1} a b] => self.0) Rat α (HasLiftT.mk.{1, succ u1} Rat α (CoeTCₓ.coe.{1, succ u1} Rat α (Rat.castCoe.{u1} α _inst_1))) n)
 but is expected to have type
-  forall {α : Type.{u2}} [_inst_1 : RatCast.{u2} α] (n : Rat), Eq.{succ u2} α (ULift.down.{u1, u2} α (RatCast.ratCast.{max u2 u1} (ULift.{u1, u2} α) (ULift.instRatCastULift.{u2, u1} α _inst_1) n)) (RatCast.ratCast.{u2} α _inst_1 n)
+  forall {α : Type.{u2}} [_inst_1 : RatCast.{u2} α] (n : Rat), Eq.{succ u2} α (ULift.down.{u1, u2} α (Rat.cast.{max u2 u1} (ULift.{u1, u2} α) (ULift.instRatCastULift.{u2, u1} α _inst_1) n)) (Rat.cast.{u2} α _inst_1 n)
 Case conversion may be inaccurate. Consider using '#align ulift.rat_cast_down ULift.rat_cast_downₓ'. -/
 @[simp]
-theorem rat_cast_down [RatCast α] (n : ℚ) : ULift.down (n : ULift α) = n :=
+theorem rat_cast_down [HasRatCast α] (n : ℚ) : ULift.down (n : ULift α) = n :=
   rfl
 #align ulift.rat_cast_down ULift.rat_cast_down

c3291da4

bump to nightly-2023-02-21-16

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

1107b979

Changes in mathlib4

mathlib3

mathlib4

13e18cfa

style: replace '.-/' by '. -/' (#11938)

Purely automatic replacement. If this is in any way controversial; I'm happy to just close this PR.

3556ded2

Diff

@@ -67,7 +67,7 @@ instance semiring [Semiring α] : Semiring (ULift α) :=
       npow_succ := fun _ _ => Monoid.npow_succ _ _ }
 #align ulift.semiring ULift.semiring
 
-/-- The ring equivalence between `ULift α` and `α`.-/
+/-- The ring equivalence between `ULift α` and `α`. -/
 def ringEquiv [NonUnitalNonAssocSemiring α] : ULift α ≃+* α where
   toFun := ULift.down
   invFun := ULift.up

13e18cfa

perf: remove overspecified fields (#6965)

This removes redundant field values of the form add := add for smaller terms and less unfolding during unification.

A list of all files containing a structure instance of the form { a1, ... with x1 := val, ... } where some xi is a field of some aj was generated by modifying the structure instance elaboration algorithm to print such overlaps to stdout in a custom toolchain.

Using that toolchain, I went through each file on the list and attempted to remove algebraic fields that overlapped and were redundant, eg add := add and not toFun (though some other ones did creep in). If things broke (which was the case in a couple of cases), I did not push further and reverted.

It is possible that pushing harder and trying to remove all redundant overlaps will yield further improvements.

12150475

Diff

@@ -48,7 +48,6 @@ instance nonUnitalNonAssocSemiring [NonUnitalNonAssocSemiring α] :
 
 instance nonAssocSemiring [NonAssocSemiring α] : NonAssocSemiring (ULift α) :=
   { ULift.addMonoidWithOne with
-      zero := (0 : ULift α), one := (1 : ULift α), add := (· + ·), mul := (· * ·),
       nsmul := AddMonoid.nsmul, natCast := fun n => ULift.up n, add_comm, left_distrib,
       right_distrib, zero_mul, mul_zero, one_mul, mul_one }
 #align ulift.non_assoc_semiring ULift.nonAssocSemiring
@@ -62,7 +61,7 @@ instance nonUnitalSemiring [NonUnitalSemiring α] : NonUnitalSemiring (ULift α)
 
 instance semiring [Semiring α] : Semiring (ULift α) :=
   { ULift.addMonoidWithOne with
-      zero := (0 : ULift α), one := 1, add := (· + ·), mul := (· * ·), nsmul := AddMonoid.nsmul,
+      nsmul := AddMonoid.nsmul,
       npow := Monoid.npow, natCast := fun n => ULift.up n, add_comm, left_distrib, right_distrib,
       zero_mul, mul_zero, mul_assoc, one_mul, mul_one, npow_zero := fun _ => Monoid.npow_zero _,
       npow_succ := fun _ _ => Monoid.npow_succ _ _ }
@@ -87,7 +86,6 @@ instance nonUnitalCommSemiring [NonUnitalCommSemiring α] : NonUnitalCommSemirin
 
 instance commSemiring [CommSemiring α] : CommSemiring (ULift α) :=
   { ULift.semiring with
-      zero := (0 : ULift α), one := (1 : ULift α), add := (· + ·), mul := (· * ·),
       nsmul := AddMonoid.nsmul, natCast := fun n => ULift.up n, npow := Monoid.npow, mul_comm }
 #align ulift.comm_semiring ULift.commSemiring

13e18cfa

chore: script to replace headers with #align_import statements (#5979)

depends on: #5966

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

89aa3a3b

Diff

@@ -2,15 +2,12 @@
 Copyright (c) 2020 Scott Morrison. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison
-
-! This file was ported from Lean 3 source module algebra.ring.ulift
-! leanprover-community/mathlib commit 13e18cfa070ea337ea960176414f5ae3a1534aae
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.Algebra.Group.ULift
 import Mathlib.Algebra.Ring.Equiv
 
+#align_import algebra.ring.ulift from "leanprover-community/mathlib"@"13e18cfa070ea337ea960176414f5ae3a1534aae"
+
 /-!
 # `ULift` instances for ring

13e18cfa

chore: Split off and golf ulift field instances (#2911)

Match https://github.com/leanprover-community/mathlib/pull/18590 and https://github.com/leanprover-community/mathlib/pull/18596

Co-authored-by: Eric Wieser <wieser.eric@gmail.com>

5163d8ce

Diff

@@ -4,12 +4,11 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Scott Morrison
 
 ! This file was ported from Lean 3 source module algebra.ring.ulift
-! leanprover-community/mathlib commit 207cfac9fcd06138865b5d04f7091e46d9320432
+! leanprover-community/mathlib commit 13e18cfa070ea337ea960176414f5ae3a1534aae
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
 import Mathlib.Algebra.Group.ULift
-import Mathlib.Algebra.Field.Defs
 import Mathlib.Algebra.Ring.Equiv
 
 /-!
@@ -157,34 +156,4 @@ instance commRing [CommRing α] : CommRing (ULift α) :=
   { ULift.ring with mul_comm }
 #align ulift.comm_ring ULift.commRing
 
-instance [RatCast α] : RatCast (ULift α) :=
-  ⟨fun a => ULift.up ↑a⟩
-
-@[simp]
-theorem rat_cast_down [RatCast α] (n : ℚ) : ULift.down (n : ULift α) = n := rfl
-#align ulift.rat_cast_down ULift.rat_cast_down
-
-instance field [Field α] : Field (ULift α) :=
-  { @ULift.nontrivial α _, ULift.commRing with
-    inv := Inv.inv
-    div := Div.div
-    zpow := fun n a => ULift.up (a.down ^ n)
-    ratCast := fun a => (a : ULift α)
-    ratCast_mk := fun a b h1 h2 => by
-      apply ULift.down_inj.1
-      dsimp [RatCast.ratCast]
-      exact Field.ratCast_mk a b h1 h2
-    qsmul := (· • ·)
-    inv_zero
-    div_eq_mul_inv
-    qsmul_eq_mul' := fun _ _ => by
-      apply ULift.down_inj.1
-      dsimp [RatCast.ratCast]
-      exact DivisionRing.qsmul_eq_mul' _ _
-    zpow_zero' := DivInvMonoid.zpow_zero'
-    zpow_succ' := DivInvMonoid.zpow_succ'
-    zpow_neg' := DivInvMonoid.zpow_neg'
-    mul_inv_cancel := fun _ ha => by simp [ULift.down_inj.1, ha] }
-#align ulift.field ULift.field
-
 end ULift

207cfac9

chore: rename HasRatCast to RatCast (#1329)

cfdf4320

Diff

@@ -157,11 +157,11 @@ instance commRing [CommRing α] : CommRing (ULift α) :=
   { ULift.ring with mul_comm }
 #align ulift.comm_ring ULift.commRing
 
-instance [HasRatCast α] : HasRatCast (ULift α) :=
+instance [RatCast α] : RatCast (ULift α) :=
   ⟨fun a => ULift.up ↑a⟩
 
 @[simp]
-theorem rat_cast_down [HasRatCast α] (n : ℚ) : ULift.down (n : ULift α) = n := rfl
+theorem rat_cast_down [RatCast α] (n : ℚ) : ULift.down (n : ULift α) = n := rfl
 #align ulift.rat_cast_down ULift.rat_cast_down
 
 instance field [Field α] : Field (ULift α) :=
@@ -172,14 +172,14 @@ instance field [Field α] : Field (ULift α) :=
     ratCast := fun a => (a : ULift α)
     ratCast_mk := fun a b h1 h2 => by
       apply ULift.down_inj.1
-      dsimp [HasRatCast.ratCast]
+      dsimp [RatCast.ratCast]
       exact Field.ratCast_mk a b h1 h2
     qsmul := (· • ·)
     inv_zero
     div_eq_mul_inv
     qsmul_eq_mul' := fun _ _ => by
       apply ULift.down_inj.1
-      dsimp [HasRatCast.ratCast]
+      dsimp [RatCast.ratCast]
       exact DivisionRing.qsmul_eq_mul' _ _
     zpow_zero' := DivInvMonoid.zpow_zero'
     zpow_succ' := DivInvMonoid.zpow_succ'

207cfac9

feat: port Algebra.Ring.Ulift (#1240)

Most of the porting consists of doing by hand what pi_instance_derive_field did.

Co-authored-by: ChrisHughes24 <chrishughes24@gmail.com>

bc2fc2dc

`algebra.ring.ulift` ⟷ `Mathlib.Algebra.Ring.ULift`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 64

algebra.ring.ulift ⟷ Mathlib.Algebra.Ring.ULift

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 64

`algebra.ring.ulift` ⟷ `Mathlib.Algebra.Ring.ULift`