PICTURE GROUPS OF FINITE TYPE AND COHOMOLOGY IN TYPE An
نویسندگان
چکیده
For every quiver of finite type we define a finitely presented group called a picture group. We construct a finite CW complex which is shown in another paper [10] to be a K(π, 1) for this picture group. In [5] another independent proof was given for this fact in the special case of type An with straight orientation and we use this CW complex to compute the integral cohomology of picture groups of type An with straight orientation. It is free abelian in every degree with ranks given by the “ballot numbers”. We also compute the ring structure on the cohomology of these groups.
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تاریخ انتشار 2014