Evaluating the twisted Morita–Mumford classes hp on
the Artin braid group Bn, we give the stable algebraic independence
of the hp's on the automorphism group of the free group,
Aut(Fn). This is sharper than the results we obtained by
restricting them to the mapping class group.
Keywords
free group, Morita-Mumford class,
automorphism group of a free group, braid group, cohomology
of groups, mapping class group