This book contains the definitions of several ring constructions used in various applications.
The concept of a groupoid-graded ring includes many of these constructions as special …

We call a group G with subgroups G1, G2 such that G= G1G2 and both N= G1∩ G2 and G1
are normal in G a semidirect product with amalgamated subgroup N. We show that if Gl is a …

In this article, we introduce what we call twisted Kronecker products of cocycles of finite
groups and show that the twisted Kronecker product of two cocycles is a Hadamard cocycle …