👉 In mathematics, the Routh theorem is a result that states that if one of two matrices A and B in an overdetermined system has rank at least two (i.e., the matrix product AB has full rank), then there exists a permutation of the rows such that the entries of the first row are all zero. This means that the solution to the system Ax=b is unique up to reordering of the columns, if b is in the column space of A. The theorem was independently discovered by
