Grad angular cutoff
= Grad angular cutoff
{c}
{title2=$\int_{S^2}B(g,n)\,dn<\infty$}
The angular collision rate is integrable at each nonzero relative velocity, with any needed speed-growth bounds stated separately. This makes the separate gain and loss integrals available under suitable velocity integrability. Non-cutoff kernels can have infinite angular collision rate and require cancellation rather than the same naive gain-loss split.