(Universidad Autónoma de Barcelona, Departamento de Matemáticas, 2005) Iranzo, M.J.; Lafuente López, Julio; Pérez Monasor, F.; Matemáticas; Matematika
In this paper we study the set of fitting classes which are right extensible by soluble groups ordered by the inclusion relation. The consideration of the associated lattices gives rise to new fitting classes and it allows to obtain some injectivity criteria for general
fitting classes.
(Real Sociedad Matemática Española, 1979) Lafuente López, Julio; Matemáticas; Matematika
All groups to be considered are finite. The main result of this paper is the following: the normal Schunck classes compose a complete and distributive lattice antiisomorphic to the lattice composed by the derived classes. It begins with a first section of machinery which establishes that the derived classes are precisely the classes of groups G such that every simple section of G appartains to a σ-closed class of simple groups; therefore the derived classes are a natural generalization of the classes of σ-groups. Finally we study the lattice properties of the normal Schunck classes relative to a class of groups.
