The Lusternik-Schniremann-category and the fundamental group
arXiv:0909.4567
Abstract
We prove that $$ \cat X\le cd(Ï_1(X))+\bigg\lceil\frac{\dim X-1}{2}\bigg\rceil$$ for every CW complex $X$ where $cd(Ï_1(X))$ denotes the cohomological dimension of the fundamental group of $X$.