intro a b xs haxs ys
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)
⊢ ∀ {a : α} {b : β a} {xs : KVChain r β} {haxs : boundLeft a xs} {ys : KVChain r β} (hays : boundLeft a ys),
    mergeWith f (KVChain.cons a b xs haxs) ys =
      KVChain.cons a b (mergeWith f xs ys) (_ : boundLeft a (mergeWith f xs ys))
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)
a : α
b : β a
xs : KVChain r β
haxs : boundLeft a xs
ys : KVChain r β
⊢ ∀ (hays : boundLeft a ys),
    mergeWith f (KVChain.cons a b xs haxs) ys =
      KVChain.cons a b (mergeWith f xs ys) (_ : boundLeft a (mergeWith f xs ys))