congr
α : Type u_1
as bs : Array α
start stop : Nat
hstart : start ≤ stop
hstop : stop ≤ bs.size
hne : ¬start = stop
hstart' : start < stop
⊢ as.size + (1 + (stop - start - 1)) = as.size + (stop - start)
case e_a
α : Type u_1
as bs : Array α
start stop : Nat
hstart : start ≤ stop
hstop : stop ≤ bs.size
hne : ¬start = stop
hstart' : start < stop
⊢ 1 + (stop - start - 1) = stop - start