An n × n complex matrix A is said to be a reflexive (anti-reflexive) matrix with respect to the generalized reflection matrix P if A = PAP (A = — PAP). The reflexive and anti-reflexive matrices have ...

Bradley W. Dickinson, Solution of Linear Equations with Rational Toeplitz Matrices, Mathematics of Computation, Vol. 34, No. 149 (Jan., 1980), pp. 227-233 ...

That technique, called matrix multiplication, previously set a hard speed limit on just how quickly linear systems could be solved. It still features in the work, but in a complementary role.