MathDB
Putnam 1986 B3

Source:

August 5, 2019
Putnam

Problem Statement

Let Γ\Gamma consist of all polynomials in xx with integer coefficients. For ff and gg in Γ\Gamma and mm a positive integer, let fg(modm)f \equiv g \pmod{m} mean that every coefficient of fgf-g is an integral multiple of mm. Let nn and pp be positive integers with pp prime. Given that f,g,h,rf,g,h,r and ss are in Γ\Gamma with rf+sg1(modp)rf+sg\equiv 1 \pmod{p} and fgh(modp)fg \equiv h \pmod{p}, prove that there exist FF and GG in Γ\Gamma with Ff(modp)F \equiv f \pmod{p}, Gg(modp)G \equiv g \pmod{p}, and FGh(modpn)FG \equiv h \pmod{p^n}.