Permanental Analog of the Rank-Nullity Theorem for Symmetric Matrices (2507.01344v1)

Abstract: The rank-nullity theorem is a core result in the study of matrices. The rank of an $n \times n$ matrix is equal to the size of its largest square submatrix with a nonzero determinant; it can be computed in $O(n^{2.37})$ time. For symmetric matrices, the rank equals to the number of nonzero eigenvalues (that is, the nonzero roots of the characteristic polynomial), which implies that the nullity equals the multiplicity of zero eigenvalue. Similar to the rank, the permanental rank of a matrix is the size of the largest square submatrix with nonzero permanent (whose computation is #P-complete), while the permanental nullity is the multiplicity of zero as a root of the permanental polynomial. In this paper, we prove a permanental analog of the rank-nullity theorem for any non-negative symmetric matrix, positive semi-definite matrix and (-1, 0, 1)-balanced symmetric matrices.