OP-00205 Partially resolved Exact positive semidefinite rank of subset-intersection matrices NA · Johnson schemes · OpenProblemsInNLA · positive semidefinite factorizations · positive semidefinite rank
OP-00262 Solution claimed Infinitesimal rigidity detects unique size-two factors in the presence of zeros NA · infinitesimal rigidity · OpenProblemsInNLA · positive semidefinite factorizations · positive semidefinite rank