Set family operations #
This file defines a few binary operations on Finset α for use in set family combinatorics.
Main declarations #
Finset.sups s t: Finset of elements of the forma ⊔ bwherea ∈ s,b ∈ t.Finset.infs s t: Finset of elements of the forma ⊓ bwherea ∈ s,b ∈ t.Finset.disjSups s t: Finset of elements of the forma ⊔ bwherea ∈ s,b ∈ tandaandbare disjoint.Finset.diffs: Finset of elements of the forma \ bwherea ∈ s,b ∈ t.Finset.compls: Finset of elements of the formaᶜwherea ∈ s.
Notation #
We define the following notation in locale FinsetFamily:
s ⊻ tforFinset.supss ⊼ tforFinset.infss ○ tforFinset.disjSups s ts \\ tforFinset.diffssᶜˢforFinset.compls
References #
[B. Bollobás, Combinatorics][bollobas1986]
s ⊻ t is the finset of elements of the form a ⊔ b where a ∈ s, b ∈ t.
Equations
- Finset.hasSups = { sups := Finset.image₂ fun (x x_1 : α) => x ⊔ x_1 }
Instances For
s ⊼ t is the finset of elements of the form a ⊓ b where a ∈ s, b ∈ t.
Equations
- Finset.hasInfs = { infs := Finset.image₂ fun (x x_1 : α) => x ⊓ x_1 }
Instances For
The finset of elements of the form a ⊔ b where a ∈ s, b ∈ t and a and b are disjoint.
Equations
- Finset.disjSups s t = Finset.image (fun (ab : α × α) => ab.1 ⊔ ab.2) (Finset.filter (fun (ab : α × α) => Disjoint ab.1 ab.2) (s ×ˢ t))
Instances For
The finset of elements of the form a ⊔ b where a ∈ s, b ∈ t and a and b are disjoint.
Equations
- FinsetFamily.«term_○_» = Lean.ParserDescr.trailingNode `FinsetFamily.term_○_ 74 74 (Lean.ParserDescr.binary `andthen (Lean.ParserDescr.symbol " ○ ") (Lean.ParserDescr.cat `term 75))
Instances For
s \\ t is the finset of elements of the form a \ b where a ∈ s, b ∈ t.
Equations
- Finset.diffs = Finset.image₂ fun (x x_1 : α) => x \ x_1
Instances For
s \\ t is the finset of elements of the form a \ b where a ∈ s, b ∈ t.
Equations
- One or more equations did not get rendered due to their size.
Instances For
sᶜˢ is the finset of elements of the form aᶜ where a ∈ s.
Equations
- Finset.compls = Finset.map { toFun := compl, inj' := ⋯ }
Instances For
sᶜˢ is the finset of elements of the form aᶜ where a ∈ s.
Equations
- FinsetFamily.«term_ᶜˢ» = Lean.ParserDescr.trailingNode `FinsetFamily.term_ᶜˢ 1024 1024 (Lean.ParserDescr.symbol "ᶜˢ")
Instances For
Alias of the forward direction of Finset.compls_nonempty.
Alias of the reverse direction of Finset.compls_nonempty.