Solvability of a nonlinear integral equation arising in kinetic theory

In the paper the question of solvability of an Urysohn type nonlinear integral equation arising in kinetic theory of gases has been studied. We prove the existence of a positive and bounded solution and also suggest an approach for the construction of a solution. We also show that there is a qualitative difference between solutions in the linear and nonlinear cases. In the nonlinear case the solution is a positive and bounded function, while the corresponding linear equation has an alternating solution, which possesses linear growth at infinity.