The Witt group of non-degenerate braided fusion categories
arXiv:1009.2117
Abstract
We give a characterization of Drinfeld centers of fusion categories as non-degenerate braided fusion categories containing a Lagrangian algebra. Further we study the quotient of the monoid of non-degenerate braided fusion categories modulo the submonoid of the Drinfeld centers and show that its formal properties are similar to those of the classical Witt group.
37 pages; many improvements in exposition thanks to the referee suggestions; new section 3.6; new remarks 3.2, 4.12, 5.2, 5.29