MathDB
Polynomials With Special Properties

Source: KöMaL A. 813

March 23, 2022
komalalgebranumber theorypolynomial

Problem Statement

Let pp be a prime number and kk be a positive integer. Let t=i=0kpi.t=\sum_{i=0}^\infty\bigg\lfloor\frac{k}{p^i}\bigg\rfloor.a) Let f(x)f(x) be a polynomial of degree kk with integer coefficients such that its leading coefficient is 11 and its constant is divisible by p.p. prove that there exists nNn\in\mathbb{N} for which pf(n),p\mid f(n), but pt+1f(n).p^{t+1}\nmid f(n).
b) Prove that the statement above is sharp, i.e. there exists a polynomial g(x)g(x) of degree k,k, integer coefficients, leading coefficient 11 and constant divisible by pp such that if pg(n)p\mid g(n) is true for a certain nN,n\in\mathbb{N}, then ptg(n)p^t\mid g(n) also holds.
Proposed by Kristóf Szabó, Budapest