Symmetry of Ext Vanishing over Non-commutative Rings
نویسنده
چکیده
It is proved for certain graded non-commutative rings that if M and N are graded bi-modules, finitely generated from either side, then the Ext groups between M and N vanish from some step if and only if the Ext groups between N and M vanish from some step. Among the rings in question are twisted homogeneous coordinate rings of elliptic curves.
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تاریخ انتشار 2004