2013/03/09 by Ravindra Bapat, Bapat, Ravindra, Ebrahim Ghorbani +1 · 1 citation
Mathematics · #Combinatorics (math.CO) #FOS: Mathematics #math.CO
paper · pdf · doi:10.48550/arxiv.1303.2177
9 pages
arxiv created 2013/03/09 · arxiv updated 2013/03/12
To a given nonsingular triangular matrix A with entries from a ring, we associate a weighted bipartite graph G(A) and give a combinatorial description of the inverse of A by employing paths in G(A). Under a certain condition, nonsingular triangular matrices A such that A and A-1 have the same zero-nonzero pattern are characterized. A combinatorial construction is given to construct outer inverses of the adjacency matrix of a weighted tree.