He addressed the International Congress of Mathematicians in Rome in 1908 on the topological foundations of Lie groups. However, after studying Schönflies ' report on set theory, he wrote to Hilbert:
Siya direksiyon sa International Congress of Mathematicians sa Roma noong 1908 sa topological pundasyon ng humiga / magsinungaling grupo. Gayunman, matapos pag-aralan Schönflies' ulat sa set theory, siya sa Hilbert wrote: