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Title:
Symmetry defects and equivariant completion

Speaker:
Nils Carqueville

Abstract:
(Generalised) orbifolds of 2d topological quantum field theories can be described by covering worldsheets of the unorbifolded theory by a network of appropriate defects A. I shall review how independence of the choice of this triangulation (i.e. invariance under Pachner moves) is equivalent to the structure of a symmetric separable Frobenius algebra on A, and discuss some of the merits of this algebraic approach. Secondly, I will explore what happens if one drops the symmetry condition on A and find interesting relations to Hochschild homology and cohomology as well as nontrvial Serre functors in the the associated D-brane categories. (Based on work with I. Brunner, D. Murfet, D. Plencner and I. Runkel.)

Link:
http://scgp.stonybrook.edu/video_portal/video.php?id=1015

Workshop:
Simons- Workshop 2012-2013ay - String-Math 2013