H\"older continuity and differentiability on subsequences

Abstract

It is shown that an arbitrary function from $D\subset \R^n$ to $\R^m$ will become $C^{0,\alpha}$-continuous in almost every $x\in D$ after restriction to a certain subset with limit point $x$. For $n\geq m$ differentiability can be obtained. Examples show the H\"older exponent $\alpha=\min\{1,\frac{n}{m}\}$ is optimal.