On the future of solutions to the massless Einstein-Vlasov system in a Bianchi I cosmology (Q776771)

The authors show that massless solutions to the Einstein-Vlasov system in a Bianchi I space-time with small anisotropy, i.e., small shear and small trace-free part of the spatial energy momentum tensor, tend to a radiation fluid in an Einstein-de Sitter space-time with the anisotropy \(\sum_{\; b}^a\sum_{\; a}^b\) and \(\tilde w^i_{\; j} \tilde w^j_{\; i}\) decaying as \(O(t^{-1/2})\).