2002/22/2

On p-semirings

On M-operators of q-lattices

Congruence submodularity

Lexico extension and a cut completion of a half l-group

Frobenius n-group algebras

An inverse matrix of an upper triangular matrix can be lower triangular

Classification systems and their lattice

Quasi-implication algebras

Free Abelian extensions in the congruence-permutable varieties