Ordered monoid and group homomorphisms #
This file defines morphisms between (additive) ordered monoids.
Types of morphisms #
OrderAddMonoidHom: Ordered additive monoid homomorphisms.OrderMonoidHom: Ordered monoid homomorphisms.OrderMonoidWithZeroHom: Ordered monoid with zero homomorphisms.OrderAddMonoidIso: Ordered additive monoid isomorphisms.OrderMonoidIso: Ordered monoid isomorphisms.
Notation #
→+o: Bundled ordered additive monoid homs. Also use for additive group homs.→*o: Bundled ordered monoid homs. Also use for group homs.→*₀o: Bundled ordered monoid with zero homs. Also use for group with zero homs.≃+o: Bundled ordered additive monoid isos. Also use for additive group isos.≃*o: Bundled ordered monoid isos. Also use for group isos.≃*₀o: Bundled ordered monoid with zero isos. Also use for group with zero isos.
Implementation notes #
There's a coercion from bundled homs to fun, and the canonical notation is to use the bundled hom as a function via this coercion.
There is no OrderGroupHom -- the idea is that OrderMonoidHom is used.
The constructor for OrderMonoidHom needs a proof of map_one as well as map_mul; a separate
constructor OrderMonoidHom.mk' will construct ordered group homs (i.e. ordered monoid homs
between ordered groups) given only a proof that multiplication is preserved,
Implicit {} brackets are often used instead of type class [] brackets. This is done when the
instances can be inferred because they are implicit arguments to the type OrderMonoidHom. When
they can be inferred from the type it is faster to use this method than to use type class inference.
Removed typeclasses #
This file used to define typeclasses for order-preserving (additive) monoid homomorphisms:
OrderAddMonoidHomClass, OrderMonoidHomClass, and OrderMonoidWithZeroHomClass.
In https://github.com/leanprover-community/mathlib4/pull/10544 we migrated from these typeclasses
to assumptions like [FunLike F M N] [MonoidHomClass F M N] [OrderHomClass F M N],
making some definitions and lemmas irrelevant.
Tags #
ordered monoid, ordered group, monoid with zero
α →+o β is the type of monotone functions α → β that preserve the OrderedAddCommMonoid
structure.
OrderAddMonoidHom is also used for ordered group homomorphisms.
When possible, instead of parametrizing results over (f : α →+o β),
you should parametrize over
(F : Type*) [FunLike F M N] [MonoidHomClass F M N] [OrderHomClass F M N] (f : F).
- toFun : α → β
- map_add' (x y : α) : (↑self.toAddMonoidHom).toFun (x + y) = (↑self.toAddMonoidHom).toFun x + (↑self.toAddMonoidHom).toFun y
- monotone' : Monotone (↑self.toAddMonoidHom).toFun
An
OrderAddMonoidHomis a monotone function.
Infix notation for OrderAddMonoidHom.
Equations
- «term_→+o_» = Lean.ParserDescr.trailingNode `«term_→+o_» 25 26 (Lean.ParserDescr.binary `andthen (Lean.ParserDescr.symbol " →+o ") (Lean.ParserDescr.cat `term 25))
α ≃+o β is the type of monotone isomorphisms α ≃ β that preserve the OrderedAddCommMonoid
structure.
OrderAddMonoidIso is also used for ordered group isomorphisms.
When possible, instead of parametrizing results over (f : α ≃+o β),
you should parametrize over
(F : Type*) [FunLike F M N] [AddEquivClass F M N] [OrderIsoClass F M N] (f : F).
- toFun : α → β
- invFun : β → α
- left_inv : Function.LeftInverse self.invFun self.toFun
- right_inv : Function.RightInverse self.invFun self.toFun
An
OrderAddMonoidIsorespects≤.
Infix notation for OrderAddMonoidIso.
Equations
- «term_≃+o_» = Lean.ParserDescr.trailingNode `«term_≃+o_» 25 26 (Lean.ParserDescr.binary `andthen (Lean.ParserDescr.symbol " ≃+o ") (Lean.ParserDescr.cat `term 25))
α →*o β is the type of functions α → β that preserve the OrderedCommMonoid structure.
OrderMonoidHom is also used for ordered group homomorphisms.
When possible, instead of parametrizing results over (f : α →*o β),
you should parametrize over
(F : Type*) [FunLike F M N] [MonoidHomClass F M N] [OrderHomClass F M N] (f : F).
- toFun : α → β
- map_mul' (x y : α) : (↑self.toMonoidHom).toFun (x * y) = (↑self.toMonoidHom).toFun x * (↑self.toMonoidHom).toFun y
- monotone' : Monotone (↑self.toMonoidHom).toFun
An
OrderMonoidHomis a monotone function.
Infix notation for OrderMonoidHom.
Equations
- «term_→*o_» = Lean.ParserDescr.trailingNode `«term_→*o_» 25 26 (Lean.ParserDescr.binary `andthen (Lean.ParserDescr.symbol " →*o ") (Lean.ParserDescr.cat `term 25))
Turn an element of a type F satisfying OrderHomClass F α β and MonoidHomClass F α β
into an actual OrderMonoidHom. This is declared as the default coercion from F to α →*o β.
Turn an element of a type F satisfying OrderHomClass F α β and AddMonoidHomClass F α β
into an actual OrderAddMonoidHom.
This is declared as the default coercion from F to α →+o β.
Any type satisfying OrderMonoidHomClass can be cast into OrderMonoidHom via
OrderMonoidHomClass.toOrderMonoidHom.
Any type satisfying OrderAddMonoidHomClass can be cast into OrderAddMonoidHom via
OrderAddMonoidHomClass.toOrderAddMonoidHom
α ≃*o β is the type of isomorphisms α ≃ β that preserve the OrderedCommMonoid structure.
OrderMonoidIso is also used for ordered group isomorphisms.
When possible, instead of parametrizing results over (f : α ≃*o β),
you should parametrize over
(F : Type*) [FunLike F M N] [MulEquivClass F M N] [OrderIsoClass F M N] (f : F).
- toFun : α → β
- invFun : β → α
- left_inv : Function.LeftInverse self.invFun self.toFun
- right_inv : Function.RightInverse self.invFun self.toFun
An
OrderMonoidIsorespects≤.
Infix notation for OrderMonoidIso.
Equations
- «term_≃*o_» = Lean.ParserDescr.trailingNode `«term_≃*o_» 25 26 (Lean.ParserDescr.binary `andthen (Lean.ParserDescr.symbol " ≃*o ") (Lean.ParserDescr.cat `term 25))
Turn an element of a type F satisfying OrderIsoClass F α β and MulEquivClass F α β
into an actual OrderMonoidIso. This is declared as the default coercion from F to α ≃*o β.
Turn an element of a type F satisfying OrderIsoClass F α β and AddEquivClass F α β
into an actual OrderAddMonoidIso.
This is declared as the default coercion from F to α ≃+o β.
Any type satisfying OrderMonoidHomClass can be cast into OrderMonoidHom via
OrderMonoidHomClass.toOrderMonoidHom.
Any type satisfying OrderAddMonoidHomClass can be cast into OrderAddMonoidHom via
OrderAddMonoidHomClass.toOrderAddMonoidHom
Any type satisfying OrderMonoidIsoClass can be cast into OrderMonoidIso via
OrderMonoidIsoClass.toOrderMonoidIso.
Any type satisfying OrderAddMonoidIsoClass can be cast into OrderAddMonoidIso via
OrderAddMonoidIsoClass.toOrderAddMonoidIso
OrderMonoidWithZeroHom α β is the type of functions α → β that preserve
the MonoidWithZero structure.
OrderMonoidWithZeroHom is also used for group homomorphisms.
When possible, instead of parametrizing results over (f : α →+ β),
you should parameterize over
(F : Type*) [FunLike F M N] [MonoidWithZeroHomClass F M N] [OrderHomClass F M N] (f : F).
- toFun : α → β
- map_mul' (x y : α) : (↑self.toMonoidWithZeroHom).toFun (x * y) = (↑self.toMonoidWithZeroHom).toFun x * (↑self.toMonoidWithZeroHom).toFun y
- monotone' : Monotone (↑self.toMonoidWithZeroHom).toFun
An
OrderMonoidWithZeroHomis a monotone function.
Infix notation for OrderMonoidWithZeroHom.
Equations
- «term_→*₀o_» = Lean.ParserDescr.trailingNode `«term_→*₀o_» 25 26 (Lean.ParserDescr.binary `andthen (Lean.ParserDescr.symbol " →*₀o ") (Lean.ParserDescr.cat `term 25))
Turn an element of a type F
satisfying OrderHomClass F α β and MonoidWithZeroHomClass F α β
into an actual OrderMonoidWithZeroHom.
This is declared as the default coercion from F to α →+*₀o β.
See also NonnegHomClass.apply_nonneg.
Equations
- OrderMonoidHom.instFunLike = { coe := fun (f : α →*o β) => (↑f.toMonoidHom).toFun, coe_injective' := ⋯ }
Equations
- OrderAddMonoidHom.instFunLike = { coe := fun (f : α →+o β) => (↑f.toAddMonoidHom).toFun, coe_injective' := ⋯ }
Reinterpret an ordered monoid homomorphism as an order homomorphism.
Equations
- f.toOrderHom = { toFun := (↑f.toMonoidHom).toFun, monotone' := ⋯ }
Reinterpret an ordered additive monoid homomorphism as an order homomorphism.
Equations
- f.toOrderHom = { toFun := (↑f.toAddMonoidHom).toFun, monotone' := ⋯ }
Copy of an OrderMonoidHom with a new toFun equal to the old one. Useful to fix
definitional equalities.
Copy of an OrderAddMonoidHom with a new toFun equal to the old one. Useful to fix
definitional equalities.
The identity map as an ordered monoid homomorphism.
Equations
- OrderMonoidHom.id α = { toMonoidHom := MonoidHom.id α, monotone' := ⋯ }
The identity map as an ordered additive monoid homomorphism.
Equations
- OrderAddMonoidHom.id α = { toAddMonoidHom := AddMonoidHom.id α, monotone' := ⋯ }
Equations
- OrderMonoidHom.instInhabited α = { default := OrderMonoidHom.id α }
Equations
- OrderAddMonoidHom.instInhabited α = { default := OrderAddMonoidHom.id α }
Composition of OrderMonoidHoms as an OrderMonoidHom.
Composition of OrderAddMonoidHoms as an OrderAddMonoidHom
1 is the homomorphism sending all elements to 1.
0 is the homomorphism sending all elements to 0.
For two ordered monoid morphisms f and g, their product is the ordered monoid morphism
sending a to f a * g a.
For two ordered additive monoid morphisms f and g, their product is the ordered
additive monoid morphism sending a to f a + g a.
Makes an ordered group homomorphism from a proof that the map preserves multiplication.
Equations
- OrderMonoidHom.mk' f hf map_mul = { toMonoidHom := MonoidHom.mk' f map_mul, monotone' := hf }
Makes an ordered additive group homomorphism from a proof that the map preserves addition.
Equations
- OrderAddMonoidHom.mk' f hf map_mul = { toAddMonoidHom := AddMonoidHom.mk' f map_mul, monotone' := hf }
The identity map as an ordered monoid isomorphism.
Equations
- OrderMonoidIso.refl α = { toMulEquiv := MulEquiv.refl α, map_le_map_iff' := ⋯ }
The identity map as an ordered additive monoid isomorphism.
Equations
- OrderAddMonoidIso.refl α = { toAddEquiv := AddEquiv.refl α, map_le_map_iff' := ⋯ }
Equations
- OrderMonoidIso.instInhabited α = { default := OrderMonoidIso.refl α }
Equations
- OrderAddMonoidIso.instInhabited α = { default := OrderAddMonoidIso.refl α }
Makes an ordered group isomorphism from a proof that the map preserves multiplication.
Equations
- OrderMonoidIso.mk' f hf map_mul = { toMulEquiv := MulEquiv.mk' f map_mul, map_le_map_iff' := ⋯ }
Makes an ordered additive group isomorphism from a proof that the map preserves addition.
Equations
- OrderAddMonoidIso.mk' f hf map_mul = { toAddEquiv := AddEquiv.mk' f map_mul, map_le_map_iff' := ⋯ }
Equations
- OrderMonoidWithZeroHom.instFunLike = { coe := fun (f : α →*₀o β) => (↑f.toMonoidWithZeroHom).toFun, coe_injective' := ⋯ }
Reinterpret an ordered monoid with zero homomorphism as an order monoid homomorphism.
Equations
- f.toOrderMonoidHom = { toFun := (↑f.toMonoidWithZeroHom).toFun, map_one' := ⋯, map_mul' := ⋯, monotone' := ⋯ }
Copy of an OrderMonoidWithZeroHom with a new toFun equal to the old one. Useful to fix
definitional equalities.
The identity map as an ordered monoid with zero homomorphism.
Equations
- OrderMonoidWithZeroHom.id α = { toMonoidWithZeroHom := MonoidWithZeroHom.id α, monotone' := ⋯ }
Equations
- OrderMonoidWithZeroHom.instInhabited α = { default := OrderMonoidWithZeroHom.id α }
Composition of OrderMonoidWithZeroHoms as an OrderMonoidWithZeroHom.
For two ordered monoid morphisms f and g, their product is the ordered monoid morphism
sending a to f a * g a.
Any ordered group is isomorphic to the units of itself adjoined with 0.
Equations
- OrderMonoidIso.unitsWithZero = { toMulEquiv := WithZero.unitsWithZeroEquiv, map_le_map_iff' := ⋯ }