Function vstd::arithmetic::power::lemma_pow_sub_add_cancel
source · pub broadcast proof fn lemma_pow_sub_add_cancel(b: int, e1: nat, e2: nat)
Expand description
requires
e1 >= e2,
ensures#[trigger] pow(b, (e1 - e2) as nat) * pow(b, e2) == pow(b, e1),
Proof that if e1 >= e2
, then b
to the power of e1
is equal
to the product of b
to the power of e1 - e2
and b
to the
power of e2