Abstract:
The spectrum $\omega(G)$ of a finite group $G$ is the set of element orders of $G$. A finite group $G$ is said to be recognizable by spectrum (briefly, recognizable) if $H\simeq G$ for every finite group $H$ such that $\omega(H)=\omega(G)$. We give two series, infinite by dimension, of finite simple classical groups recognizable by spectrum.
Keywords:recognition by spectrum, finite orthogonal group.