The stationary Boltzmann equation for a two-component gas in the slab

The stationary Boltzmann equation for hard forces in the context of a two-component gas is considered in the slab. An L1 existence theorem is proved when one component satisfies a given indata profile and the other component satisfies diffuse reflection at the boundaries. Weak L1 compactness is extracted from the control of the entropy production term. Trace at the boundaries are also controlled.