Reductions of Tensor Categories Modulo Primes
Author(s)Gelaki, Shlomo; Etingof, Pavel I.
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We study good (i.e., semisimple) reductions of semisimple rigid tensor categories modulo primes. A prime p is called good for a semisimple rigid tensor category C if such a reduction exists (otherwise, it is called bad). It is clear that a good prime must be relatively prime to the Müger squared norm |V|[superscript 2] of any simple object V of C. We show, using the Ito–Michler theorem in finite group theory, that for group-theoretical fusion categories, the converse is true. While the converse is false for general fusion categories, we obtain results about good and bad primes for many known fusion categories (e.g., for Verlinde categories). We also state some questions and conjectures regarding good and bad primes.
Original manuscript February 12, 2011
DepartmentMassachusetts Institute of Technology. Department of Mathematics
Communications in Algebra
Taylor & Francis
Etingof, Pavel, and Shlomo Gelaki. “Reductions of Tensor Categories Modulo Primes.” Communications in Algebra 39, no. 12 (December 2011): 4634-4643.