Closed sets #
We define a few types of closed sets in a topological space.
Main Definitions #
For a topological space α
,
TopologicalSpace.Closeds α
: The type of closed sets.TopologicalSpace.Clopens α
: The type of clopen sets.
Closed sets #
The type of closed subsets of a topological space.
Instances For
Equations
- TopologicalSpace.Closeds.instSetLike = { coe := TopologicalSpace.Closeds.carrier, coe_injective' := ⋯ }
See Note [custom simps projection].
Equations
Instances For
The closure of a set, as an element of TopologicalSpace.Closeds
.
Equations
- TopologicalSpace.Closeds.closure s = { carrier := closure s, closed' := ⋯ }
Instances For
The galois coinsertion between sets and opens.
Equations
- TopologicalSpace.Closeds.gi = { choice := fun (s : Set α) (hs : ↑(TopologicalSpace.Closeds.closure s) ≤ s) => { carrier := s, closed' := ⋯ }, gc := ⋯, le_l_u := ⋯, choice_eq := ⋯ }
Instances For
Equations
- One or more equations did not get rendered due to their size.
The type of closed sets is inhabited, with default element the empty set.
Closed sets in a topological space form a coframe.
Equations
- TopologicalSpace.Closeds.coframeMinimalAxioms = Order.Coframe.MinimalAxioms.mk ⋯
Instances For
Equations
- TopologicalSpace.Closeds.instCoframe = Order.Coframe.ofMinimalAxioms TopologicalSpace.Closeds.coframeMinimalAxioms
The term of TopologicalSpace.Closeds α
corresponding to a singleton.
Equations
- TopologicalSpace.Closeds.singleton x = { carrier := {x}, closed' := ⋯ }
Instances For
The complement of a closed set as an open set.
Instances For
The complement of an open set as a closed set.
Instances For
TopologicalSpace.Closeds.compl
as an OrderIso
to the order dual of
TopologicalSpace.Opens α
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
TopologicalSpace.Opens.compl
as an OrderIso
to the order dual of
TopologicalSpace.Closeds α
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
in a T1Space
, atoms of TopologicalSpace.Closeds α
are precisely the
TopologicalSpace.Closeds.singleton
s.
in a T1Space
, coatoms of TopologicalSpace.Opens α
are precisely complements of singletons:
(TopologicalSpace.Closeds.singleton x).compl
.
Clopen sets #
The type of clopen sets of a topological space.
Instances For
Equations
- TopologicalSpace.Clopens.instSetLike = { coe := fun (s : TopologicalSpace.Clopens α) => s.carrier, coe_injective' := ⋯ }
See Note [custom simps projection].
Equations
Instances For
Reinterpret a clopen as an open.
Equations
- s.toOpens = { carrier := ↑s, is_open' := ⋯ }
Instances For
Equations
- TopologicalSpace.Clopens.instMax = { max := fun (s t : TopologicalSpace.Clopens α) => { carrier := ↑s ∪ ↑t, isClopen' := ⋯ } }
Equations
- TopologicalSpace.Clopens.instMin = { min := fun (s t : TopologicalSpace.Clopens α) => { carrier := ↑s ∩ ↑t, isClopen' := ⋯ } }
Equations
- TopologicalSpace.Clopens.instSDiff = { sdiff := fun (s t : TopologicalSpace.Clopens α) => { carrier := ↑s \ ↑t, isClopen' := ⋯ } }
Equations
- TopologicalSpace.Clopens.instHImp = { himp := fun (s t : TopologicalSpace.Clopens α) => { carrier := ↑s ⇨ ↑t, isClopen' := ⋯ } }
Equations
- TopologicalSpace.Clopens.instHasCompl = { compl := fun (s : TopologicalSpace.Clopens α) => { carrier := (↑s)ᶜ, isClopen' := ⋯ } }
Equations
- TopologicalSpace.Clopens.instBooleanAlgebra = Function.Injective.booleanAlgebra SetLike.coe ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯ ⋯
Equations
- TopologicalSpace.Clopens.instSProdProd = { sprod := fun (s : TopologicalSpace.Clopens α) (t : TopologicalSpace.Clopens β) => { carrier := ↑s ×ˢ ↑t, isClopen' := ⋯ } }
Irreducible closed sets #
The type of irreducible closed subsets of a topological space.
- carrier : Set α
the carrier set, i.e. the points in this set
- is_irreducible' : IsIrreducible self.carrier
- is_closed' : IsClosed self.carrier
Instances For
Equations
- TopologicalSpace.IrreducibleCloseds.instSetLike = { coe := TopologicalSpace.IrreducibleCloseds.carrier, coe_injective' := ⋯ }
See Note [custom simps projection].
Equations
Instances For
The term of TopologicalSpace.IrreducibleCloseds α
corresponding to a singleton.
Equations
- TopologicalSpace.IrreducibleCloseds.singleton x = { carrier := {x}, is_irreducible' := ⋯, is_closed' := ⋯ }
Instances For
The equivalence between IrreducibleCloseds α
and {x : Set α // IsIrreducible x ∧ IsClosed x }
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The equivalence between IrreducibleCloseds α
and {x : Set α // IsClosed x ∧ IsIrreducible x }
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The equivalence IrreducibleCloseds α ≃ { x : Set α // IsIrreducible x ∧ IsClosed x }
is an
order isomorphism.
Equations
- TopologicalSpace.IrreducibleCloseds.orderIsoSubtype α = TopologicalSpace.IrreducibleCloseds.equivSubtype.toOrderIso ⋯ ⋯
Instances For
The equivalence IrreducibleCloseds α ≃ { x : Set α // IsClosed x ∧ IsIrreducible x }
is an
order isomorphism.
Equations
- TopologicalSpace.IrreducibleCloseds.orderIsoSubtype' α = TopologicalSpace.IrreducibleCloseds.equivSubtype'.toOrderIso ⋯ ⋯