Exponents of almost simple groups and an application to the restricted Burnside problem.
Extension of complexes of groups
Complexes of groups over ordered simplicial complexes are generalizations to higher dimensions of graphs of groups. We first relate them to complexes of spaces by considering their classifying space . Then we develop their homological algebra aspects. We define the notions of homology and cohomology of a complex of groups with coefficients in a -module and show the existence of free resolutions. We apply those notions to study extensions of complexes of groups with constant or abelian kernel....
Extensions of abelian by hyper-(cyclic or finite) groups (II)
Extensions of Certain Homomorphisms of Subsemi-groups to Homomorphisms of Groups
Extensions of homomorphisms of subsemigroups of a group.
Extensions of partially ordered partial abelian monoids
The notion of a partially ordered partial abelian monoid is introduced and extensions of partially ordered abelian monoids by partially ordered abelian groups are studied. Conditions for the extensions to exist are found. The cases when both the above mentioned structures have the Riesz decomposition property, or are lattice ordered, are treated. Some applications to effect algebras and MV-algebras are shown.
Extensions realising a faithful abstract kernel and their automorphisms.