# Regularity and approximation of strong solutions to rate-independent systems

## TL;DR

This paper proves the existence and uniqueness of Hölder-regular strong solutions for rate-independent systems and demonstrates their approximation via a convergent finite element numerical scheme.

## Contribution

It introduces a novel approach to establish regularity and uniqueness of strong solutions for rate-independent systems, along with a compatible numerical approximation scheme.

## Key findings

- Existence of Hölder-regular strong solutions
- Higher regularity guarantees uniqueness
- Numerical scheme converges at a rate consistent with solution regularity

## Abstract

Rate-independent systems arise in a number of applications. Usually, weak solutions to such problems with potentially very low regularity are considered, requiring mathematical techniques capable of handling nonsmooth functions. In this work we prove the existence of H\"older-regular strong solutions for a class of rate-independent systems. We also establish additional higher regularity results that guarantee the uniqueness of strong solutions. The proof proceeds via a time-discrete Rothe approximation and careful elliptic regularity estimates depending in a quantitative way on the (local) convexity of the potential featuring in the model. In the second part of the paper we show that our strong solutions may be approximated by a fully discrete numerical scheme based on a spatial finite element discretization, whose rate of convergence is consistent with the regularity of strong solutions whose existence and uniqueness are established.