MathDB
2020 PUMaC Algebra A6 / B8

Source:

January 1, 2022
algebra

Problem Statement

Given integer nn, let WnW_n be the set of complex numbers of the form re2qiπre^{2qi\pi}, where qq is a rational number so that qnZq_n \in Z and rr is a real number. Suppose that p is a polynomial of degree 2 \ge 2 such that there exists a non-constant function f:WnCf : W_n \to C so that p(f(x))p(f(y))=f(xy)p(f(x))p(f(y)) = f(xy) for all x,yWnx, y \in W_n. If pp is the unique monic polynomial of lowest degree for which such an ff exists for n=65n = 65, find p(10)p(10).