Documentation

Mathlib.Algebra.Order.Hom.Ring

Ordered ring homomorphisms #

Homomorphisms between ordered (semi)rings that respect the ordering.

Main definitions #

Notation #

Implementation notes #

This file used to define typeclasses for order-preserving ring homomorphisms and isomorphisms. In #10544, we migrated from assumptions like [FunLike F R S] [OrderRingHomClass F R S] to assumptions like [FunLike F R S] [OrderHomClass F R S] [RingHomClass F R S], making some typeclasses and instances irrelevant.

Tags #

ordered ring homomorphism, order homomorphism

structure OrderRingHom (α : Type u_6) (β : Type u_7) [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] extends RingHom :
Type (max u_6 u_7)

OrderRingHom α β is the type of monotone semiring homomorphisms from α to β.

When possible, instead of parametrizing results over (f : OrderRingHom α β), you should parametrize over (F : Type*) [OrderRingHomClass F α β] (f : F).

When you extend this structure, make sure to extend OrderRingHomClass.

  • toFun : αβ
  • map_one' : self.toFun 1 = 1
  • map_mul' : ∀ (x y : α), self.toFun (x * y) = self.toFun x * self.toFun y
  • map_zero' : self.toFun 0 = 0
  • map_add' : ∀ (x y : α), self.toFun (x + y) = self.toFun x + self.toFun y
  • monotone' : Monotone self.toFun

    The proposition that the function preserves the order.

Instances For

OrderRingHom α β is the type of monotone semiring homomorphisms from α to β.

When possible, instead of parametrizing results over (f : OrderRingHom α β), you should parametrize over (F : Type*) [OrderRingHomClass F α β] (f : F).

When you extend this structure, make sure to extend OrderRingHomClass.

Equations
structure OrderRingIso (α : Type u_6) (β : Type u_7) [Mul α] [Mul β] [Add α] [Add β] [LE α] [LE β] extends RingEquiv :
Type (max u_6 u_7)

OrderRingHom α β is the type of order-preserving semiring isomorphisms between α and β.

When possible, instead of parametrizing results over (f : OrderRingIso α β), you should parametrize over (F : Type*) [OrderRingIsoClass F α β] (f : F).

When you extend this structure, make sure to extend OrderRingIsoClass.

  • toFun : αβ
  • invFun : βα
  • left_inv : Function.LeftInverse self.invFun self.toFun
  • right_inv : Function.RightInverse self.invFun self.toFun
  • map_mul' : ∀ (x y : α), self.toFun (x * y) = self.toFun x * self.toFun y
  • map_add' : ∀ (x y : α), self.toFun (x + y) = self.toFun x + self.toFun y
  • map_le_map_iff' : ∀ {a b : α}, self.toFun a self.toFun b a b

    The proposition that the function preserves the order bijectively.

Instances For

OrderRingHom α β is the type of order-preserving semiring isomorphisms between α and β.

When possible, instead of parametrizing results over (f : OrderRingIso α β), you should parametrize over (F : Type*) [OrderRingIsoClass F α β] (f : F).

When you extend this structure, make sure to extend OrderRingIsoClass.

Equations
def OrderRingHomClass.toOrderRingHom {F : Type u_1} {α : Type u_2} {β : Type u_3} [FunLike F α β] [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] [OrderHomClass F α β] [RingHomClass F α β] (f : F) :
α →+*o β

Turn an element of a type F satisfying OrderHomClass F α β and RingHomClass F α β into an actual OrderRingHom. This is declared as the default coercion from F to α →+*o β.

Equations
  • f = let __src := f; { toRingHom := __src, monotone' := }
instance instCoeTCOrderRingHom {F : Type u_1} {α : Type u_2} {β : Type u_3} [FunLike F α β] [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] [OrderHomClass F α β] [RingHomClass F α β] :
CoeTC F (α →+*o β)

Any type satisfying OrderRingHomClass can be cast into OrderRingHom via OrderRingHomClass.toOrderRingHom.

Equations
  • instCoeTCOrderRingHom = { coe := OrderRingHomClass.toOrderRingHom }
def OrderRingIsoClass.toOrderRingIso {F : Type u_1} {α : Type u_2} {β : Type u_3} [EquivLike F α β] [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] [OrderIsoClass F α β] [RingEquivClass F α β] (f : F) :
α ≃+*o β

Turn an element of a type F satisfying OrderIsoClass F α β and RingEquivClass F α β into an actual OrderRingIso. This is declared as the default coercion from F to α ≃+*o β.

Equations
  • f = let __src := f; { toRingEquiv := __src, map_le_map_iff' := }
instance instCoeTCOrderRingIso {F : Type u_1} {α : Type u_2} {β : Type u_3} [EquivLike F α β] [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] [OrderIsoClass F α β] [RingEquivClass F α β] :
CoeTC F (α ≃+*o β)

Any type satisfying OrderRingIsoClass can be cast into OrderRingIso via OrderRingIsoClass.toOrderRingIso.

Equations
  • instCoeTCOrderRingIso = { coe := OrderRingIsoClass.toOrderRingIso }

Ordered ring homomorphisms #

def OrderRingHom.toOrderAddMonoidHom {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) :
α →+o β

Reinterpret an ordered ring homomorphism as an ordered additive monoid homomorphism.

Equations
def OrderRingHom.toOrderMonoidWithZeroHom {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) :
α →*₀o β

Reinterpret an ordered ring homomorphism as an order homomorphism.

Equations
instance OrderRingHom.instFunLikeOrderRingHom {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] :
FunLike (α →+*o β) α β
Equations
  • OrderRingHom.instFunLikeOrderRingHom = { coe := fun (f : α →+*o β) => f.toFun, coe_injective' := }
theorem OrderRingHom.toFun_eq_coe {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) :
f.toFun = f
theorem OrderRingHom.ext {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] {f : α →+*o β} {g : α →+*o β} (h : ∀ (a : α), f a = g a) :
f = g
@[simp]
theorem OrderRingHom.toRingHom_eq_coe {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) :
f.toRingHom = f
@[simp]
theorem OrderRingHom.coe_coe_ringHom {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) :
f = f
@[simp]
theorem OrderRingHom.coe_coe_orderAddMonoidHom {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) :
f = f
@[simp]
theorem OrderRingHom.coe_coe_orderMonoidWithZeroHom {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) :
f = f
theorem OrderRingHom.coe_ringHom_apply {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) (a : α) :
f a = f a
theorem OrderRingHom.coe_orderAddMonoidHom_apply {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) (a : α) :
f a = f a
theorem OrderRingHom.coe_orderMonoidWithZeroHom_apply {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) (a : α) :
f a = f a
def OrderRingHom.copy {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) (f' : αβ) (h : f' = f) :
α →+*o β

Copy of an OrderRingHom with a new toFun equal to the old one. Useful to fix definitional equalities.

Equations
@[simp]
theorem OrderRingHom.coe_copy {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) (f' : αβ) (h : f' = f) :
(OrderRingHom.copy f f' h) = f'
theorem OrderRingHom.copy_eq {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) (f' : αβ) (h : f' = f) :
def OrderRingHom.id (α : Type u_2) [NonAssocSemiring α] [Preorder α] :
α →+*o α

The identity as an ordered ring homomorphism.

Equations
@[simp]
theorem OrderRingHom.coe_id (α : Type u_2) [NonAssocSemiring α] [Preorder α] :
(OrderRingHom.id α) = id
@[simp]
theorem OrderRingHom.id_apply {α : Type u_2} [NonAssocSemiring α] [Preorder α] (a : α) :
def OrderRingHom.comp {α : Type u_2} {β : Type u_3} {γ : Type u_4} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] [NonAssocSemiring γ] [Preorder γ] (f : β →+*o γ) (g : α →+*o β) :
α →+*o γ

Composition of two OrderRingHoms as an OrderRingHom.

Equations
  • One or more equations did not get rendered due to their size.
@[simp]
theorem OrderRingHom.coe_comp {α : Type u_2} {β : Type u_3} {γ : Type u_4} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] [NonAssocSemiring γ] [Preorder γ] (f : β →+*o γ) (g : α →+*o β) :
(OrderRingHom.comp f g) = f g
@[simp]
theorem OrderRingHom.comp_apply {α : Type u_2} {β : Type u_3} {γ : Type u_4} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] [NonAssocSemiring γ] [Preorder γ] (f : β →+*o γ) (g : α →+*o β) (a : α) :
(OrderRingHom.comp f g) a = f (g a)
theorem OrderRingHom.comp_assoc {α : Type u_2} {β : Type u_3} {γ : Type u_4} {δ : Type u_5} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] [NonAssocSemiring γ] [Preorder γ] [NonAssocSemiring δ] [Preorder δ] (f : γ →+*o δ) (g : β →+*o γ) (h : α →+*o β) :
@[simp]
theorem OrderRingHom.comp_id {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) :
@[simp]
theorem OrderRingHom.id_comp {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α →+*o β) :
@[simp]
theorem OrderRingHom.cancel_right {α : Type u_2} {β : Type u_3} {γ : Type u_4} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] [NonAssocSemiring γ] [Preorder γ] {f₁ : β →+*o γ} {f₂ : β →+*o γ} {g : α →+*o β} (hg : Function.Surjective g) :
OrderRingHom.comp f₁ g = OrderRingHom.comp f₂ g f₁ = f₂
@[simp]
theorem OrderRingHom.cancel_left {α : Type u_2} {β : Type u_3} {γ : Type u_4} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] [NonAssocSemiring γ] [Preorder γ] {f : β →+*o γ} {g₁ : α →+*o β} {g₂ : α →+*o β} (hf : Function.Injective f) :
OrderRingHom.comp f g₁ = OrderRingHom.comp f g₂ g₁ = g₂
Equations
Equations

Ordered ring isomorphisms #

def OrderRingIso.toOrderIso {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (f : α ≃+*o β) :
α ≃o β

Reinterpret an ordered ring isomorphism as an order isomorphism.

Equations
  • f = { toEquiv := f.toEquiv, map_rel_iff' := }
instance OrderRingIso.instEquivLikeOrderRingIso {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] :
EquivLike (α ≃+*o β) α β
Equations
  • OrderRingIso.instEquivLikeOrderRingIso = { coe := fun (f : α ≃+*o β) => f.toFun, inv := fun (f : α ≃+*o β) => f.invFun, left_inv := , right_inv := , coe_injective' := }
instance OrderRingIso.instOrderIsoClassOrderRingIsoInstEquivLikeOrderRingIso {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] :
OrderIsoClass (α ≃+*o β) α β
Equations
  • =
instance OrderRingIso.instRingEquivClassOrderRingIsoInstEquivLikeOrderRingIso {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] :
RingEquivClass (α ≃+*o β) α β
Equations
  • =
theorem OrderRingIso.toFun_eq_coe {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (f : α ≃+*o β) :
f.toFun = f
theorem OrderRingIso.ext {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] {f : α ≃+*o β} {g : α ≃+*o β} (h : ∀ (a : α), f a = g a) :
f = g
@[simp]
theorem OrderRingIso.coe_mk {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (e : α ≃+* β) (h : ∀ {a b : α}, e.toFun a e.toFun b a b) :
{ toRingEquiv := e, map_le_map_iff' := h } = e
@[simp]
theorem OrderRingIso.mk_coe {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (e : α ≃+*o β) (h : ∀ {a b : α}, (e).toFun a (e).toFun b a b) :
{ toRingEquiv := e, map_le_map_iff' := h } = e
@[simp]
theorem OrderRingIso.toRingEquiv_eq_coe {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (f : α ≃+*o β) :
f.toRingEquiv = f
@[simp]
theorem OrderRingIso.toOrderIso_eq_coe {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (f : α ≃+*o β) :
f = f
@[simp]
theorem OrderRingIso.coe_toRingEquiv {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (f : α ≃+*o β) :
f = f
@[simp]
theorem OrderRingIso.coe_toOrderIso {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (f : α ≃+*o β) :
f = f
def OrderRingIso.refl (α : Type u_2) [Mul α] [Add α] [LE α] :
α ≃+*o α

The identity map as an ordered ring isomorphism.

Equations
@[simp]
theorem OrderRingIso.refl_apply (α : Type u_2) [Mul α] [Add α] [LE α] (x : α) :
@[simp]
theorem OrderRingIso.coe_ringEquiv_refl (α : Type u_2) [Mul α] [Add α] [LE α] :
@[simp]
theorem OrderRingIso.coe_orderIso_refl (α : Type u_2) [Mul α] [Add α] [LE α] :
def OrderRingIso.symm {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (e : α ≃+*o β) :
β ≃+*o α

The inverse of an ordered ring isomorphism as an ordered ring isomorphism.

Equations
def OrderRingIso.Simps.symm_apply {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (e : α ≃+*o β) :
βα

See Note [custom simps projection]

Equations
@[simp]
theorem OrderRingIso.symm_symm {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (e : α ≃+*o β) :
def OrderRingIso.trans {α : Type u_2} {β : Type u_3} {γ : Type u_4} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] [Mul γ] [Add γ] [LE γ] (f : α ≃+*o β) (g : β ≃+*o γ) :
α ≃+*o γ

Composition of OrderRingIsos as an OrderRingIso.

Equations
theorem OrderRingIso.trans_toRingEquiv {α : Type u_2} {β : Type u_3} {γ : Type u_4} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] [Mul γ] [Add γ] [LE γ] (f : α ≃+*o β) (g : β ≃+*o γ) :
(OrderRingIso.trans f g).toRingEquiv = RingEquiv.trans f.toRingEquiv g.toRingEquiv
@[simp]
theorem OrderRingIso.trans_toRingEquiv_aux {α : Type u_2} {β : Type u_3} {γ : Type u_4} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] [Mul γ] [Add γ] [LE γ] (f : α ≃+*o β) (g : β ≃+*o γ) :
(OrderRingIso.trans f g) = RingEquiv.trans f.toRingEquiv g.toRingEquiv
@[simp]
theorem OrderRingIso.trans_apply {α : Type u_2} {β : Type u_3} {γ : Type u_4} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] [Mul γ] [Add γ] [LE γ] (f : α ≃+*o β) (g : β ≃+*o γ) (a : α) :
(OrderRingIso.trans f g) a = g (f a)
@[simp]
theorem OrderRingIso.self_trans_symm {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (e : α ≃+*o β) :
@[simp]
theorem OrderRingIso.symm_trans_self {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] (e : α ≃+*o β) :
theorem OrderRingIso.symm_bijective {α : Type u_2} {β : Type u_3} [Mul α] [Add α] [LE α] [Mul β] [Add β] [LE β] :
Function.Bijective OrderRingIso.symm
def OrderRingIso.toOrderRingHom {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α ≃+*o β) :
α →+*o β

Reinterpret an ordered ring isomorphism as an ordered ring homomorphism.

Equations
@[simp]
@[simp]
theorem OrderRingIso.coe_toOrderRingHom {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] (f : α ≃+*o β) :
f = f
theorem OrderRingIso.toOrderRingHom_injective {α : Type u_2} {β : Type u_3} [NonAssocSemiring α] [Preorder α] [NonAssocSemiring β] [Preorder β] :
Function.Injective OrderRingIso.toOrderRingHom

Uniqueness #

There is at most one ordered ring homomorphism from a linear ordered field to an archimedean linear ordered field. Reciprocally, such an ordered ring homomorphism exists when the codomain is further conditionally complete.

There is at most one ordered ring homomorphism from a linear ordered field to an archimedean linear ordered field.

Equations
  • =

There is at most one ordered ring isomorphism between a linear ordered field and an archimedean linear ordered field.

Equations
  • =

There is at most one ordered ring isomorphism between an archimedean linear ordered field and a linear ordered field.

Equations
  • =