see schoolbook algorithm for the n^3 bound: https://en.wikipedia.org/wiki/Computational_complexity_of_matrix_multiplication https://en.wikipedia.org/wiki/Comput

see schoolbook algorithm for the n^3 bound: https://en.wikipedia.org/wiki/Computational_complexity_of_matrix_multiplication https://en.wikipedia.org/wiki/Computational_complexity_of_ma... It comes from directly applying the definition of matrix multiplication on a square matrix.