Canonical ordering theorems, a first attempt
Commutative/noncommutative rank of linear matrices and subspaces of matrices of low rank.
Completing block Hermitian matrices with maximal and minimal ranks and inertias.
Computation of rigidity of order for one simple matrix
We shall compute the exact value of rigidity of the triangular matrix with entries 0 and 1.
Counting with groups and rings.
Covering in the set of principal ideals in the semigroup of binary relations.