The R-matrix method of a FusionRing computes R^{ab}_c. If a=b it is somewhat delicate to compute. Previously a method of Leduc and Ram was used, and computation of F-matrices by #30423 seemed to show that there was an error. The difficulty is probably not in the result of Leduc and Ram (actually due to Reshetikhin) but in the implementation. This ticket replaces the algorithm with one of Bonderson, Delaney, Galindo, Rowell, Tran and Wang. Preliminary testing by computing F-matrices seems to show that this method gives correct results. (Thanks to Eric Rowell for suggesting this approach.)

CC: @tscrim @sagetrac-sage-combinat @dwbump @willieab @physicstravels

Component: combinatorics

Keywords: FusionRing

Author: Daniel Bump, Willie Aboumrad, Travis Scrimshaw

Branch/Commit: 9c6a639

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/31284