Combing Euclidean buildings.
Combins of Semidrect Products and 3-Manifold Groups.
Commensurability of graph products.
Commensurations of Out
Let Out(Fn) denote the outer automorphism group of the free group Fn with n>3. We prove that for any finite index subgroup Γ<Out(Fn), the group Aut(Γ) is isomorphic to the normalizer of Γ in Out(Fn). We prove that Γ is co-Hopfian: every injective homomorphism Γ→Γ is surjective. Finally, we prove that the abstract commensurator Comm(Out(Fn)) is isomorphic to Out(Fn).
Commensurations of the Johnson kernel.
Commensurator subgroups of surface groups.
Comments on gentleness of endomorphism algebras.
Comments on the permutation property for semigroups.
Common summands in partitions
Commutation of operations and its relationship with Menger and Mann superpositions
The article considers a problem from Trokhimenko paper [13] concerning the study of abstract properties of commutations of operations and their connection with the Menger and Mann superpositions. Namely, abstract characterizations of some classes of operation algebras, whose signature consists of arbitrary families of commutations of operations, Menger and Mann superpositions and their various connections are found. Some unsolved problems are given at the end of the article.
Commutative and noncommutative invariant theory
Commutative archimedean cancellative semigroups without idempotent
Commutative cancellative semigroups with two generators
Commutative diagrams for the inflation-restriction sequence
Commutative distributive groupoids
Commutative group algebras of highly torsion-complete abelian -groups
A new class of abelian -groups with all high subgroups isomorphic is defined. Commutative modular and semisimple group algebras over such groups are examined. The results obtained continue our recent statements published in Comment. Math. Univ. Carolinae (2002).
Commutative images of rational languages and the abelian kernel of a monoid
Natural algorithms to compute rational expressions for recognizable languages, even those which work well in practice, may produce very long expressions. So, aiming towards the computation of the commutative image of a recognizable language, one should avoid passing through an expression produced this way. We modify here one of those algorithms in order to compute directly a semilinear expression for the commutative image of a recognizable language. We also give a second modification of the algorithm...
Commutative images of rational languages and the Abelian kernel of a monoid
Natural algorithms to compute rational expressions for recognizable languages, even those which work well in practice, may produce very long expressions. So, aiming towards the computation of the commutative image of a recognizable language, one should avoid passing through an expression produced this way. We modify here one of those algorithms in order to compute directly a semilinear expression for the commutative image of a recognizable language. We also give a second modification of the algorithm...
Commutative modular group algebras of -mixed and -splitting abelian -groups
Let be a -mixed abelian group and is a commutative perfect integral domain of . Then, the first main result is that the group of all normalized invertible elements is a -group if and only if is a -group. In particular, the second central result is that if is a -group, the -algebras isomorphism between the group algebras and for an arbitrary but fixed group implies is a -mixed abelian -group and even more that the high subgroups of and are isomorphic, namely, . Besides,...
Commutative monoids all of whose principal ideals are projective.