Lattice homomorphisms #
This file defines (bounded) lattice homomorphisms.
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- ⊓.
- SupBotHom: Finitary supremum homomorphisms. Maps which preserve- ⊔and- ⊥.
- InfTopHom: Finitary infimum homomorphisms. Maps which preserve- ⊓and- ⊤.
- LatticeHom: Lattice homomorphisms. Maps which preserve- ⊔and- ⊓.
- BoundedLatticeHom: Bounded lattice homomorphisms. Maps which preserve- ⊤,- ⊥,- ⊔and- ⊓.
Typeclasses #
TODO #
Do we need more intersections between BotHom, TopHom and lattice homomorphisms?
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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The type of bounded lattice homomorphisms from α to β.
- toFun : α → β
- A - BoundedLatticeHompreserves the top element.- Do not use this directly. Use - map_topinstead.
- A - BoundedLatticeHompreserves the bottom element.- Do not use this directly. Use - map_botinstead.
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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
SupBotHomClass F α β states that F is a type of finitary supremum-preserving morphisms.
You should extend this class when you extend SupBotHom.
- A - SupBotHomClassmorphism preserves the bottom element.
Instances
InfTopHomClass F α β states that F is a type of finitary infimum-preserving morphisms.
You should extend this class when you extend SupBotHom.
- An - InfTopHomClassmorphism preserves the top element.
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
BoundedLatticeHomClass F α β states that F is a type of bounded lattice morphisms.
You should extend this class when you extend BoundedLatticeHom.
- A - BoundedLatticeHomClassmorphism preserves the top element.
- A - BoundedLatticeHomClassmorphism preserves the bottom element.
Instances
We can regard an injective map preserving binary infima as an order embedding.
Equations
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Special case of map_compl for boolean algebras.
Special case of map_sdiff for boolean algebras.
Special case of map_symmDiff for boolean algebras.
Equations
- instCoeTCSupHomOfSupHomClass = { coe := fun (f : F) => { toFun := ⇑f, map_sup' := ⋯ } }
Equations
- instCoeTCInfHomOfInfHomClass = { coe := fun (f : F) => { toFun := ⇑f, map_inf' := ⋯ } }
Equations
- instCoeTCSupBotHomOfSupBotHomClass = { coe := fun (f : F) => { toFun := ⇑f, map_sup' := ⋯, map_bot' := ⋯ } }
Equations
- instCoeTCInfTopHomOfInfTopHomClass = { coe := fun (f : F) => { toFun := ⇑f, map_inf' := ⋯, map_top' := ⋯ } }
Equations
- instCoeTCLatticeHomOfLatticeHomClass = { coe := fun (f : F) => { toFun := ⇑f, map_sup' := ⋯, map_inf' := ⋯ } }
Equations
- One or more equations did not get rendered due to their size.
Supremum homomorphisms #
Equations
- SupHom.instFunLike = { coe := SupHom.toFun, coe_injective' := ⋯ }
Equations
- SupHom.instInhabited α = { default := SupHom.id α }
The constant function as a SupHom.
Equations
- SupHom.const α b = { toFun := fun (x : α) => b, map_sup' := ⋯ }
Instances For
Equations
- SupHom.instMax = { max := fun (f g : SupHom α β) => { toFun := ⇑f ⊔ ⇑g, map_sup' := ⋯ } }
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
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' := ⋯ }
Equations
- InfHom.instInhabited α = { default := InfHom.id α }
The constant function as an InfHom.
Equations
- InfHom.const α b = { toFun := fun (x : α) => b, map_inf' := ⋯ }
Instances For
Equations
- InfHom.instMin = { min := fun (f g : InfHom α β) => { toFun := ⇑f ⊓ ⇑g, map_inf' := ⋯ } }
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
Subtype.val as an InfHom.
Equations
- InfHom.subtypeVal Pinf = { toFun := Subtype.val, map_inf' := ⋯ }
Instances For
Finitary supremum homomorphisms #
Equations
- SupBotHom.instInhabited α = { default := SupBotHom.id α }
Equations
- SupBotHom.instSemilatticeSup = Function.Injective.semilatticeSup (fun (f : SupBotHom α β) => ⇑f) ⋯ ⋯
Equations
Subtype.val as a SupBotHom.
Equations
- SupBotHom.subtypeVal Pbot Psup = { toSupHom := SupHom.subtypeVal Psup, map_bot' := ⋯ }
Instances For
Finitary infimum homomorphisms #
Equations
- InfTopHom.instInhabited α = { default := InfTopHom.id α }
Equations
- InfTopHom.instSemilatticeInf = Function.Injective.semilatticeInf (fun (f : InfTopHom α β) => ⇑f) ⋯ ⋯
Equations
Subtype.val as an InfTopHom.
Equations
- InfTopHom.subtypeVal Ptop Pinf = { toInfHom := InfHom.subtypeVal Pinf, map_top' := ⋯ }
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.
Instances For
id as a LatticeHom.
Equations
- LatticeHom.id α = { toFun := id, map_sup' := ⋯, map_inf' := ⋯ }
Instances For
Equations
- LatticeHom.instInhabited α = { default := LatticeHom.id α }
Composition of LatticeHoms as a LatticeHom.
Instances For
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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Bounded lattice homomorphisms #
Reinterpret a BoundedLatticeHom as a SupBotHom.
Equations
- f.toSupBotHom = { toSupHom := f.toSupHom, map_bot' := ⋯ }
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Reinterpret a BoundedLatticeHom as an InfTopHom.
Equations
- f.toInfTopHom = { toFun := f.toFun, map_inf' := ⋯, map_top' := ⋯ }
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Reinterpret a BoundedLatticeHom as a BoundedOrderHom.
Equations
- f.toBoundedOrderHom = { toFun := f.toFun, monotone' := ⋯, map_top' := ⋯, map_bot' := ⋯ }
Instances For
Equations
- BoundedLatticeHom.instFunLike = { coe := fun (f : BoundedLatticeHom α β) => f.toFun, coe_injective' := ⋯ }
Copy of a BoundedLatticeHom with a new toFun equal to the old one. Useful to fix
definitional equalities.
Instances For
id as a BoundedLatticeHom.
Equations
- BoundedLatticeHom.id α = { toLatticeHom := LatticeHom.id α, map_top' := ⋯, map_bot' := ⋯ }
Instances For
Equations
- BoundedLatticeHom.instInhabited α = { default := BoundedLatticeHom.id α }
Composition of BoundedLatticeHoms as a BoundedLatticeHom.
Equations
- f.comp g = { toLatticeHom := f.comp g.toLatticeHom, map_top' := ⋯, map_bot' := ⋯ }
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Subtype.val as a BoundedLatticeHom.
Equations
- BoundedLatticeHom.subtypeVal Pbot Ptop Psup Pinf = { toLatticeHom := LatticeHom.subtypeVal Psup Pinf, map_top' := ⋯, map_bot' := ⋯ }
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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.
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Reinterpret a bounded lattice homomorphism as a bounded lattice homomorphism between the dual bounded lattices.
Equations
- One or more equations did not get rendered due to their size.
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Prod #
Natural projection homomorphism from α × β to α.
Equations
- LatticeHom.fst = { toFun := Prod.fst, map_sup' := ⋯, map_inf' := ⋯ }
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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' := ⋯ }
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Adjoins a ⊤ to the domain and codomain of a SupHom.
Equations
- f.withTop = { toFun := WithTop.map ⇑f, map_sup' := ⋯ }
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Adjoins a ⊥ to the domain and codomain of a SupHom.
Equations
- f.withBot = { toFun := Option.map ⇑f, map_sup' := ⋯, map_bot' := ⋯ }
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Adjoins a ⊤ to the codomain of a SupHom.
Equations
- f.withTop' = { toFun := fun (a : WithTop α) => Option.elim a ⊤ ⇑f, map_sup' := ⋯ }
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Adjoins a ⊥ to the domain of a SupHom.
Equations
- f.withBot' = { toFun := fun (a : WithBot α) => Option.elim a ⊥ ⇑f, map_sup' := ⋯, map_bot' := ⋯ }
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Adjoins a ⊤ to the domain and codomain of an InfHom.
Equations
- f.withTop = { toFun := Option.map ⇑f, map_inf' := ⋯, map_top' := ⋯ }
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Adjoins a ⊥ to the domain and codomain of an InfHom.
Equations
- f.withBot = { toFun := Option.map ⇑f, map_inf' := ⋯ }
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Adjoins a ⊤ to the codomain of an InfHom.
Equations
- f.withTop' = { toFun := fun (a : WithTop α) => Option.elim a ⊤ ⇑f, map_inf' := ⋯, map_top' := ⋯ }
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Adjoins a ⊥ to the codomain of an InfHom.
Equations
- f.withBot' = { toFun := fun (a : WithBot α) => Option.elim a ⊥ ⇑f, map_inf' := ⋯ }
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Adjoins a ⊤ to the domain and codomain of a LatticeHom.
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Adjoins a ⊥ to the domain and codomain of a LatticeHom.
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Adjoins a ⊤ and ⊥ to the domain and codomain of a LatticeHom.
Equations
- f.withTopWithBot = { toLatticeHom := f.withBot.withTop, map_top' := ⋯, map_bot' := ⋯ }
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Adjoins a ⊥ to the codomain of a LatticeHom.
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Adjoins a ⊥ to the domain and codomain of a LatticeHom.
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Adjoins a ⊤ and ⊥ to the codomain of a LatticeHom.
Equations
- f.withTopWithBot' = { toLatticeHom := f.withBot'.withTop', map_top' := ⋯, map_bot' := ⋯ }