Abstract:
After a brief history of commutation problems, with an analysis of solutions and obstructions, we turn attention to the approximate commutation problem in the context of a pair of unitary matrices. Using parameters identified by Eilers, Loring, and Petersen which capture the obstruction to a general solution, we supply a quantitative strengthening of their result using an analogous result of Kachkovskiy and Safarov in the hermitian setting.
Based on joint work with Adam Dor-On and Ilya Kachkovskiy.