2 problems

The sparsity conjecture for minimally AP-irreducible sign pattern matrices
Let $A$ be a minimally AP-irreducible sign pattern matrix of order $n$ whose diagonal entries are all zero. A sign pattern matrix $A$ is minimally AP-irreducible if it is AP-irredu…
openmatrix-positivity sign-pattern-matrices spectral-graph-theory
0 responses
07
Li et al.'s rational sign-pattern minimum-rank conjecture
Li et al.'s conjecture. If $r\geqslant t-2$ , then the minimum rank of $S$ over the rationals is also $r$ .
opencombinatorics matrix-rank sign-pattern-matrices
0 responses
04

The sparsity conjecture for minimally AP-irreducible sign pattern matrices