Some Estimates on the Boltzmann Collision Operator

The paper presents some new estimates on the gain term of the Boltzmann collision operator. For Maxwellian molecules, it is shown that the L∞-norm of the gain term can be bounded in terms of the L1- and L∞-norm of the density function f. In the case of more general collision kernels, like the hard-sphere interaction potential, the gain term is estimated pointwise by the L∞-norm of the density function and the loss term of the Boltzmann collision operator.