fact: Definition ord_prime_le a b:= (a <o omega0 -> b <o omega0 -> b <=o a) /\ (forall p, ordinalp p -> b = oopow (oopow p) -> exists2 q, p <=o q & a = oopow (oopow q)).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)