We investigate the solvability of equations
Q(f, f) + epsilon (2)Deltaf = 0
in term of nonnegative integrable densities f is an element of L-+(1)(R-3).
Here, Q(f, f) is a generalized collision operator. If Q is the Boltzmann o
perator, the only solution is 0. In contrast. we show that if Q is the pseu
do-Maxwellian collision operator for granular flow, then there are non-triv
ial weak solutions of (star).