  We show that for collinear processes, i.e. processes where the incoming and
outgoing momenta are aligned along the same line, the S-matrix of the tree
level 2+1 dimensional Thirring model factorizes: any S - matrix element is a
product of $2\rightarrow 2$ elements. In particular this means nullification of
all collinear $2 \rightarrow n$ amplitudes for $n > 2$.
