《曹锡华代数论坛》
时间：2010.6.1 15:15---16:15
地点：数学楼讲学厅102室
题目：A cohomology theory for grading-restricted
vertex algebras(阶化限制顶点代数的上同调理论)
讲演人： 黄一知教授 （美国Rutgers大学）
[摘要] We introduce a cohomology theory for grading-restricted vertex algebras. For each nonnegative integer, we have an inverse system {H^{n}_{m}(V, W)}_{min Z_+} of a grading-restricted vertex algebra V with coefficients in a V-module W. When n=0, H^{0}_{m}(V, W)=W. When n=1, H^{1}_{m}(V, W) for all positive integers m are linearly isomorphic to the space of derivations from V to W. When n=2, there is an additional second cohomologyH^{2}_{1/2}(V, W), which correspond to square-zero extensions of V and to first order deformations of V when W=V.