MathDB
Another n-variable polynomial

Source: Russian TST 2021, Day 7 P3

March 21, 2023
algebrapolynomial

Problem Statement

Given an integer n3n \geqslant 3 the polynomial f(x1,,xn)f(x_1, \ldots, x_n) with integer coefficients is called good if f(0,,0)=0f(0,\ldots, 0) = 0 and f(x1,,xn)=f(xπ1,,xπn),f(x_1, \ldots, x_n)=f(x_{\pi_1}, \ldots, x_{\pi_n}),for any permutation of π\pi of the numbers 1,,n1,\ldots, n. Denote by J\mathcal{J} the set of polynomials of the form p1q1++pmqm,p_1q_1+\cdots+p_mq_m,where mm is a positive integer and q1,,qmq_1,\ldots , q_m are polynomials with integer coefficients, and p1,,pmp_1,\ldots , p_m are good polynomials. Find the smallest natural number DD{} such that each monomial of degree DD{} lies in the set J\mathcal{J}.