noncomputable def
PFun.ofGraph
{α : Type u_1}
{β : Type u_2}
(g : α → β → Prop)
(_hg : ∀ (a : α) (b b' : β), g a b → g a b' → b = b')
:
α →. β
Equations
- PFun.ofGraph g _hg a = { Dom := ∃ (b : β), g a b, get := fun (h : ∃ (b : β), g a b) => h.choose }
Instances For
theorem
PFun.get_eq
{α : Type u_2}
{β : Type u_1}
{g : α → β → Prop}
{hg : ∀ (a : α) (b b' : β), g a b → g a b' → b = b'}
(a : α)
(b : β)
(h : g a b)
:
(PFun.ofGraph g hg a).get ⋯ = b
@[simp]
theorem
PFun.ofGraph_dom
{α : Type u_1}
{β : Type u_2}
{g : α → β → Prop}
{hg : ∀ (a : α) (b b' : β), g a b → g a b' → b = b'}
:
(PFun.ofGraph g hg).Dom = {a : α | ∃ (b : β), g a b}