On locally repeated values of arithmetic functions over $\mathbb F_q[T]$

Abstract

The frequency of occurrence of "locally repeated" values of arithmetic functions is a common theme in analytic number theory, for instance in the Erd\H{o}s-Mirsky problem on coincidences of the divisor function at consecutive integers, the analogous problem for the Euler totient function, and the quantitative conjectures of Erd\H{o}s, Pomerance and Sark\H{o}zy and of Graham, Holt and Pomerance on the frequency of occurrences. In this paper we introduce the corresponding problems in the setting of polynomials over a finite field, and completely solve them in the large finite field limit.