Matrices all of whose principal submatrices of some order have a nonzero permanent
The authors determine the maximum number of 1s in an irreducible (0, 1) matrix of order \(n\) such that for some integer \(k\), all principal submatrices of order \(k\), not all of order \(k - 1\), have a positive permanent.
scientific article; zbMATH DE number 803753