On a class of modular numerical semigroups.
On a class of semigroups with symmetric presentations.
On a conjecture of Brown.
On a problem of n(2)-permutable semigroups.
On a theorem of Šutov.
On algebraic closure and amalgamation of semigroups.
On autogenerating systems
On bands, free bands and identities.
On bases and maximal ideals in semigroups
On binomial set-theoretic complete intersections in characteristic p.
On certain finitely based varieties of semigroups.
On certain two generator monoids.
On commuting generalized inverses in semigroups.
On complete -ideals in semigroups
On congruence permutable -sets
An algebraic structure is said to be congruence permutable if its arbitrary congruences and satisfy the equation , where denotes the usual composition of binary relations. To an arbitrary -set satisfying , we assign a semigroup on the base set containing a zero element , and examine the connection between the congruence permutability of the -set and the semigroup .
On finitely generated monoids of matrices with entries in
On finitely generated submonoids of N k
On finitely generated subsemigroups of a free semigroup.
On finiteness conditions for Rees matrix semigroups
Let be a Rees matrix semigroup where is a semigroup, and are index sets, and is a matrix with entries from , and let be the ideal generated by all the entries of . If has finite index in , then we prove that is periodic (locally finite) if and only if is periodic (locally finite). Moreover, residual finiteness and having solvable word problem are investigated.
On Free Commutative Groupoids