Hilbert's twenty-third problem

Hilbert's twenty-third problem is the last of Hilbert problems set out in a celebrated list compiled in 1900 by David Hilbert. It entails the further development of the calculus of variations.

This mathematics-related article is a stub. You can help Wikipedia by expanding it.

Hilbert's problems
I \| II \| III \| IV \| V \| VI \| VII \| VIII \| IX \| X \| XI \| XII \| XIII \| XIV \| XV\| XVI \| XVII \| XVIII \| XIX \| XX \| XXI \| XXII \| XXIII