cases heq
β : Sort ?u.17044
α : Type u_1
f : β → α → β
b✝ : β
h : α → α → α
inst✝ : Std.Associative h
as : Array α
b c : α
start stop : Nat
hstart : start ≤ stop
hstop : stop ≤ as.size
heq : start = stop
⊢ foldl h (h b c) as start stop = h b (foldl h c as start stop)
case refl
β : Sort ?u.17044
α : Type u_1
f : β → α → β
b✝ : β
h : α → α → α
inst✝ : Std.Associative h
as : Array α
b c : α
start : Nat
hstart : start ≤ start
hstop : start ≤ as.size
⊢ foldl h (h b c) as start start = h b (foldl h c as start start)