MathDB
IMOC 2021 N1

Source: IMOC 2021 N1

August 12, 2021
number theory

Problem Statement

This problem consists of four parts.
1. Show that for any nonzero integers m,n,m,n, and prime pp, we have vp(mn)=vp(m)+vp(n).v_p(mn)=v_p(m)+v_p(n).
2. Show that if an off prime pp, a positive integer kk and integers a,ba,b satisfy p  pabp \nmid ~^\text{'}~p|a-b and pkp\nmid k, then vp(akbk)=vp(ab).v_p(a^k-b^k)=v_p(a-b).
3. Show that if pp is an off prime with pabp|a-b and pa,bp\nmid a,b, then vp(apbp)=vp(ab)+1)v_p(a^p-b^p)=v_p(a-b)+1).
4. Show that if an odd prime pp, a positive integer kk and integers a,ba,b satisfy pa,b  pabp\nmid a,b ~^\text{'}~ p|a-b, then vp(akbk)=vp(ab)v_p(a^k-b^k)=v_p(a-b).
Proposed by LTE.