%0 Journal Article %T Nonlinearity of matrix groups %A Martin Kassabov %A Mark Sapir %J Mathematics %D 2009 %I arXiv %X The aim of this note is to answer a question by Guoliang Yu of whether the group $EL_3(Z)$, where $Z$ is the free (non-commutative) ring, has any faithful linear representations over a field. We prove, in particular, that for every (unitary associative) ring $R$, the group $EL_3(R)$ has a faithful finite dimensional complex representation if and only if $R$ has a finite index ideal that has a faithful finite dimensional complex representation. %U http://arxiv.org/abs/0904.3153v3