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→2 elements. In particular this means nullification of
all collinear 2→n amplitudes for n>2.Comment: latex , 8 pp., 2 fig. not include