A Bruhat order for the class of -matrices with row sum vector and column sum vector .
A canonical directly infinite ring
Let be the set of nonnegative integers and the ring of integers. Let be the ring of matrices over generated by the following two matrices: one obtained from the identity matrix by shifting the ones one position to the right and the other one position down. This ring plays an important role in the study of directly finite rings. Calculation of invertible and idempotent elements of yields that the subrings generated by them coincide. This subring is the sum of the ideal consisting of...
A computation of positive one-peak posets that are Tits-sincere
A complete list of positive Tits-sincere one-peak posets is provided by applying combinatorial algorithms and computer calculations using Maple and Python. The problem whether any square integer matrix is ℤ-congruent to its transpose is also discussed. An affirmative answer is given for the incidence matrices and the Tits matrices of positive one-peak posets I.
A Factorization of an Integral 2 x 2 Matrix Via a Rational Method.
A matrix inequality for Möbius functions.
A note on consecutive ones in a binary matrix.
A note on Fibonacci matrices of even degree.
A note on indecomposability of Boolean matrices
A note on the Hankel transform of the central binomial coefficients.
A problem on matrices
An analysis of GCD and LCM matrices via the -factorization.
An Example on Strong Equivalence of Positive Integral Matrices.
An upper bound for the norm of a gcd-related matrix.