POSITIVE SIMILARITY SOLUTIONS FOR A DISCRETE VELOCITY BOLTZMAN COAGULATION-FRAGMENTATION MODEL

We consider the coagulation-fragmentation model of Slemrod and coworke rs which is essentially the two-dimensional Broadwell model including inelastic collisions. We construct two classes of similarity solutions (variable eta = x - zeta t), positive for eta is an element of(- infi nity, infinity): the Rankine-Hugoniot solutions and the scalar Riccati similarity solutions. Previous solutions were built up with positivit y along half of the x-axis. For the two classes, we determine in the p arameter space, building up the solutions, domains corresponding to po sitive solutions.