MathDB
Prove that a_i and a_j exist for every prime p

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October 5, 2010
modular arithmeticnumber theory proposednumber theory

Problem Statement

Let pp be a prime number and a1,a2,,a(p+1)/2a_1, a_2, \ldots, a_{(p+1)/2} different natural numbers less than or equal to p.p. Prove that for each natural number rr less than or equal to pp, there exist two numbers (perhaps equal) aia_i and aja_j such that paiaj(modr).p \equiv a_i a_j \pmod r.