Unbounded lattice homomorphisms #
This file defines unbounded lattice homomorphisms. Bounded lattice homomorphisms are defined in
Mathlib/Order/Hom/BoundedLattice.lean.
We use the DFunLike design, so each type of morphisms has a companion typeclass which is meant to
be satisfied by itself and all stricter types.
Types of morphisms #
SupHom: Maps which preserve⊔.InfHom: Maps which preserve⊓.LatticeHom: Lattice homomorphisms. Maps which preserve⊔and⊓.
Typeclasses #
The type of ⊔-preserving functions from α to β.
- toFun : α → β
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The type of ⊓-preserving functions from α to β.
- toFun : α → β
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The type of lattice homomorphisms from α to β.
- toFun : α → β
A
LatticeHompreserves infima.Do not use this directly. Use
map_infinstead.
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SupHomClass F α β states that F is a type of ⊔-preserving morphisms.
You should extend this class when you extend SupHom.
A
SupHomClassmorphism preserves suprema.
Instances
InfHomClass F α β states that F is a type of ⊓-preserving morphisms.
You should extend this class when you extend InfHom.
An
InfHomClassmorphism preserves infima.
Instances
LatticeHomClass F α β states that F is a type of lattice morphisms.
You should extend this class when you extend LatticeHom.
A
LatticeHomClassmorphism preserves infima.
Instances
We can regard an injective map preserving binary infima as an order embedding.
Equations
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Supremum homomorphisms #
Equations
- SupHom.instFunLike = { coe := SupHom.toFun, coe_injective' := ⋯ }
The constant function as a SupHom.
Equations
- SupHom.const α b = { toFun := fun (x : α) => b, map_sup' := ⋯ }
Instances For
Equations
- SupHom.instSemilatticeSup = Function.Injective.semilatticeSup (fun (f : SupHom α β) => ⇑f) ⋯ ⋯
Equations
- SupHom.instBot = { bot := SupHom.const α ⊥ }
Equations
- SupHom.instTop = { top := SupHom.const α ⊤ }
Equations
Equations
Equations
Alias of the reverse direction of SupHom.mk_le_mk.
Subtype.val as a SupHom.
Equations
- SupHom.subtypeVal Psup = { toFun := Subtype.val, map_sup' := ⋯ }
Instances For
Infimum homomorphisms #
Equations
- InfHom.instFunLike = { coe := InfHom.toFun, coe_injective' := ⋯ }
The constant function as an InfHom.
Equations
- InfHom.const α b = { toFun := fun (x : α) => b, map_inf' := ⋯ }
Instances For
Equations
- InfHom.instSemilatticeInf = Function.Injective.semilatticeInf (fun (f : InfHom α β) => ⇑f) ⋯ ⋯
Equations
- InfHom.instBot = { bot := InfHom.const α ⊥ }
Equations
- InfHom.instTop = { top := InfHom.const α ⊤ }
Equations
Equations
Equations
Alias of the reverse direction of InfHom.mk_le_mk.
Subtype.val as an InfHom.
Equations
- InfHom.subtypeVal Pinf = { toFun := Subtype.val, map_inf' := ⋯ }
Instances For
Lattice homomorphisms #
Reinterpret a LatticeHom as an InfHom.
Instances For
Equations
- LatticeHom.instFunLike = { coe := fun (f : LatticeHom α β) => f.toFun, coe_injective' := ⋯ }
Copy of a LatticeHom with a new toFun equal to the old one. Useful to fix definitional
equalities.
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id as a LatticeHom.
Equations
- LatticeHom.id α = { toFun := id, map_sup' := ⋯, map_inf' := ⋯ }
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Equations
- LatticeHom.instInhabited α = { default := LatticeHom.id α }
Composition of LatticeHoms as a LatticeHom.
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Subtype.val as a LatticeHom.
Equations
- LatticeHom.subtypeVal Psup Pinf = { toSupHom := SupHom.subtypeVal Psup, map_inf' := ⋯ }
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An order homomorphism from a linear order is a lattice homomorphism.
Reinterpret an order homomorphism to a linear order as a LatticeHom.
Equations
- OrderHomClass.toLatticeHom α β f = { toFun := ⇑f, map_sup' := ⋯, map_inf' := ⋯ }
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Dual homs #
Reinterpret a supremum homomorphism as an infimum homomorphism between the dual lattices.
Equations
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Reinterpret an infimum homomorphism as a supremum homomorphism between the dual lattices.
Equations
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Reinterpret a lattice homomorphism as a lattice homomorphism between the dual lattices.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Prod #
Natural projection homomorphism from α × β to α.
Equations
- LatticeHom.fst = { toFun := Prod.fst, map_sup' := ⋯, map_inf' := ⋯ }
Instances For
Natural projection homomorphism from α × β to β.
Equations
- LatticeHom.snd = { toFun := Prod.snd, map_sup' := ⋯, map_inf' := ⋯ }
Instances For
Pi #
Evaluation as a lattice homomorphism.
Equations
- Pi.evalLatticeHom i = { toFun := Function.eval i, map_sup' := ⋯, map_inf' := ⋯ }