Monday, July 9, 2018

elementary number theory - Let p be a prime. Prove that p divides abpbap for all integers a and b.



Let p be a prime. Prove that p divides abpbap for all integers
a and b.


Answer



abpbap=ab(bp1ap1)



If p|ab, then p|(abpbap) and also if pab, then gcd(p,a)=gcd(p,b)=1,bp1ap11(modp) (by Fermat's little theorem).



This further implies that p|(bp1ap1)p|(abpbap).




Q.E.D.


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