It is demonstrated how classes of linear (n, k)-codes can be enumerated using cycle index polynomials and other methods from algebraic combinatorics. Some results of joined work [9] with Prof. Kerber from the University of Bayreuth on the enumeration of linear codes over GF (q) are presented. Furthermore I will give an introduction to enumeration under finite group actions. At first let me draw...

Let X be a geometrically irreducible smooth projective curve defined over a field k. Assume that X has a k–rational point; fix a k–rational point x ∈ X . From these data we construct an affine group scheme GX defined over the field k as well as a principal GX–bundle EGX over the curve X . The group scheme GX is given by a Q–graded neutral Tannakian category built out of all strongly semistable ...

In this paper we focus on a special class of commutative local‎ ‎rings called SPAP-rings and study the relationship between this‎ ‎class and other classes of rings‎. ‎We characterize the structure of‎ ‎modules and especially‎, ‎the prime submodules of free modules over‎ ‎an SPAP-ring and derive some basic properties‎. ‎Then we answer the‎ ‎question of Lam and Reyes about strongly Oka ideals fam...

The electronic conductance at zero temperature through a quantum wire with side-connected asymmetric quantum ring (as a scatter system) is theoretically studied using the non-interacting Hamiltonian Anderson tunneling method. In this paper we concentrate on the configuration of the quantum dot rings. We show that the asymmetric structure of QD-scatter system strongly influences the amplitude an...

We show that a Dedekind-finite, semi-π-regular ring with a “nice” topology is an א0-exchange ring, and the same holds true for a strongly clean ring with a “nice” topology. We generalize the argument to show that a Dedekind-finite, semi-regular ring with a “nice” topology is a full exchange ring. Putting these results in the language of modules, we show that a cohopfian module with finite excha...