On the distance problem over finite p-adic rings

TL;DR

This paper investigates the distance problem over finite p-adic rings, providing sharp results in odd dimensions, clarifying conjectures in even dimensions, and introducing new restriction estimates and group theoretic methods.

Contribution

It offers new restriction estimates and a simplified, flexible approach to the distance problem over finite p-adic rings, extending recent results.

Findings

Sharp results in odd dimensions

Support for the distance conjecture in certain sets

A new $4/3$-parallel result in two dimensions

Abstract

In this paper, we study the distance problem in the setting of finite p-adic rings. In odd dimensions, our results are essentially sharp. In even dimensions, we clarify the conjecture and provide examples to support it. Surprisingly, compared to the finite field case, in this setting, we are able to provide a large family of sets such that the distance conjecture holds. By developing new restriction type estimates associated to circles and orbits, with a group theoretic argument, we will prove the $4/3$-parallel result in the two dimensions. This answers a question raised by Alex Iosevich. In a more general scenario, the existence/distribution of geometric/graph configurations will be also considered in this paper. Our results present improvements and extensions of recent results due to Ben Lichtin (2019, 2023). In comparison with Lichtin's method, our approach is much simpler and flexible, which is also one of the novelties in this paper.