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Composing into number of integers with lower order

Source: Iranian third number theory finals problem 3

August 15, 2019
number theory

Problem Statement

Let a,ma,m be positive integers such that Ordm(a)Ord_m (a) is odd and for any integers x,yx,y so that
1.xya(modm)xy \equiv a \pmod m
2.Ordm(x)Ordm(a)Ord_m(x) \le Ord_m(a)
3.Ordm(y)Ordm(a)Ord_m(y) \le Ord_m(a)
We have either Ordm(x)Ordm(a)Ord_m(x)|Ord_m(a) or Ordm(y)Ordm(a)Ord_m(y)|Ord_m(a).prove that Ordm(a)Ord_m(a) contains at most one prime factor.