On Characterizations of Divided Monoids

On Centralizers of Monoids

For a monoid M of k-valued unary operations, the centralizer M∗ is the clone consisting of all k-valued multi-variable operations which commute with every operation in M . First we give a sufficient condition for a monoid M to have the least clone as its centralizer. Then using this condition we determine centralizers of all monoids containing the symmetric group. AMS Mathematics Subject Classi...

On the U-WPF Acts over Monoids

Valdis Laan in [5] introduced an extension of strong flatness which is called weak pullback flatness. In this paper we introduce a new property of acts over monoids, called U-WPF which is an extension of weak pullback flatness and give a classification of monoids by this property of their acts and also a classification of monoids when this property of acts implies others. We also show that regu...

On Singular Artin Monoids

In this paper we study some combinatorial aspects of the singular Artin monoids. Firstly, we show that a singular Artin monoid SA can be presented as a semidirect product of a graph monoid with its associated Artin group A. Such a decomposition implies that a singular Artin monoid embeds in a group. Secondly, we give a solution to the word problem for the FC type singular Artin monoids. Afterwa...

On Presentations of Commutative Monoids

In this paper, all the monoids considered are commutative. If S is a monoid generated by {m1, . . . ,mn}, then S is isomorphic to a quotient monoid of N by the kernel congruence σ of the map φ : N → S, φ(k1, . . . , kn) = ∑n i=1 kimi. Under this setting, a finite presentation for S is a finite subset ρ of Nn×Nn such that the congruence generated by ρ is equal to σ. Rédei proves in [5] that ever...

On Cartesian Monoids