Sign idempotent sign patterns similar to nonnegative sign patterns

Eventually Nonnegative Matrices and their Sign Patterns

A matrix A ∈ Rn×n is eventually nonnegative (respectively, eventually positive) if there exists a positive integer k0 such that for all k ≥ k0, A ≥ 0 (respectively, A > 0). Here inequalities are entrywise and all matrices are real and square. An eigenvalue of A is dominant if its magnitude is equal to the spectral radius of A. A matrix A has the strong Perron-Frobenius property if A has a uniqu...

Sign Patterns for Eigenmatrices of Nonnegative Matrices

For a square (0, 1,−1) sign pattern matrix S, denote the qualitative class of S by Q(S). In this paper, we investigate the relationship between sign patterns and matrices that diagonalise an irreducible nonnegative matrix. We explicitly describe the sign patterns S such that every matrix in Q(S) diagonalises some irreducible nonnegative matrix. Further, we characterise the sign patterns S such ...

On nonnegative sign equivalent and sign similar factorizations of matrices

Sign Patterns That Allow a Positive or Nonnegative Left Inverse

An m by n sign pattern S is an m by n matrix with entries in {+,−, 0}. Such a sign pattern allows a positive (resp., nonnegative) left inverse, provided that there exist an m by n matrix A with the sign pattern S and an n by m matrix B with only positive (resp., nonnegative) entries satisfying BA = In, where In is the n by n identity matrix. For m > n ≥ 2, a characterization of m by n sign patt...

Sign patterns that require a positive or nonnegative left inverse

An m by n sign pattern A is an m by n matrix with entries in {+,−, 0}. The sign pattern A requires a positive (resp. nonnegative) left inverse provided each real matrix with sign pattern A has a left inverse with all entries positive (resp. nonnegative). In this paper, necessary and sufficient conditions are given for a sign pattern to require a positive or nonnegative left inverse. It is also ...