intro c hac
α : Type u
r : α → α → Prop
inst✝¹ : StrictLinearOrder r
inst✝ : DecidableRel r
β : α → Type v
f : (a : α) → β a → β a → Option (β a)
xs : KVChain (flip r) β
ys : KVChain r β
hxsys : hingeable xs ys
a : α
b : β a
haxs : boundLeft a xs
⊢ ∀ {c : α}, r a c → boundLeft c (insertWithAux f xs ys hxsys a b haxs).val.fst
α : Type u
r : α → α → Prop
inst✝¹ : StrictLinearOrder r
inst✝ : DecidableRel r
β : α → Type v
f : (a : α) → β a → β a → Option (β a)
xs : KVChain (flip r) β
ys : KVChain r β
hxsys : hingeable xs ys
a : α
b : β a
haxs : boundLeft a xs
c : α
hac : r a c
⊢ boundLeft c (insertWithAux f xs ys hxsys a b haxs).val.fst