On some problems of Petrich concerning Brück and Reilly semigroups.
On some properties of Brandt groupoids.
On some properties of pronormal subgroups
New results on tight connections among pronormal, abnormal and contranormal subgroups of a group have been established. In particular, new characteristics of pronormal and abnormal subgroups have been obtained.
On some properties of the syntactic semigroup of a very pure subsemigroup
On some (pseudo) involutions in the Riordan group.
On some questions concerning permutable subgroups of finitely generated groups and projectivities of perfect groups
On some reductive group actions on affine space II.
On some representations of hypergroups
On Some Results of Atkin and Lehner.
On some soluble groups in which -subgroups form a lattice
The article is dedicated to groups in which the set of abnormal and normal subgroups (-subgroups) forms a lattice. A complete description of these groups under the additional restriction that every counternormal subgroup is abnormal is obtained.
On some spaces of linear functionals on the algebras for locally compact groups
On some subgroup chains related to Kneser’s theorem
A recent result of Balandraud shows that for every subset of an abelian group there exists a non trivial subgroup such that holds only if . Notice that Kneser’s Theorem only gives .This strong form of Kneser’s theorem follows from some nice properties of a certain poset investigated by Balandraud. We consider an analogous poset for nonabelian groups and, by using classical tools from Additive Number Theory, extend some of the above results. In particular we obtain short proofs of Balandraud’s...
On some subgroups of infinite rank Butler groups
On some subsemigroups of a free semigroup.
On some systems of equations with constraints in a free group. – Addenda. (Sur certains systèmes d'équations avec constraintes dans un groupe libre. – Addenda.)
On some systems of equations with constraints in a free group. (Sur certains systèmes d'équations avec contraintes dans un groupe libre.)
On some type of radicals on a semigroup
On Spaces of Kleinian Groups
On spaces with periodic cohomology.
On special -groups
In questo lavoro viene data una caratterizzazione di quei -gruppi nilpotenti di classe due ed esponente che sono speciali. Vengono inoltre studiate alcune costruzioni, automorfismi e sottogruppi abeliani di -gruppi speciali.