We investigate the notion of cyclicity for convolutional codes as it has been introduced in the papers [15, 18]. Codes of this type are described as submodules of F[z]n with some additional generalized cyclic structure but also as specific left ideals in a skew polynomial ring. Extending a result of [15], we show in a purely algebraic setting that these ideals are always principal. This leads t...

‎for a set of non-negative integers~$l$‎, ‎the $l$-intersection number of a graph is the smallest number~$l$ for which there is an assignment of subsets $a_v subseteq {1,dots‎, ‎l}$ to vertices $v$‎, ‎such that every two vertices $u,v$ are adjacent if and only if $|a_u cap a_v|in l$‎. ‎the bipartite $l$-intersection number is defined similarly when the conditions are considered only for the ver...

In this paper, we study the dualization in distributive lattices, a generalization of well-known hypergraph problem. We particular propose equivalent formulations problem terms graphs, hypergraphs, and posets. It is known that amounts to generate all minimal transversals hypergraph, or dominating sets graph. new framework, poset on vertices given together with input (hyper)graph, “ideal solutio...

Introduction. Relations between the multiplication ring of a ring (= non-associative ring)1 and the ring itself have been pointed out by a number of writers [l-7]. In the present note it is shown that the ideal lattice of a ring with unit element is isomorphic to the sublattice of all right ideals of the multiplication ring which contain the annihilator of the unit. A corresponding result is ob...

For an element x of a ring R, let A (x), Ar(x), and A(x) denote, respectively, the left, right and two-sided annihilator of x in R. For a set X , we denote cardX by |X|; and say that a subset Y of X is large in X if |Y | = |X|. We prove that if x is any nilpotent element and I is any infinite ideal of R, then A(x) ∩ I is large in I , and in particular |A (x)| = |Ar(x)| = |A(x)| = |R|. The last ...

We introduce and study a transfer map between ideals of the universal enveloping algebras of two members of a reductive dual pair of Lie algebras. Its definition is motivated by the approach to the real Howe duality through the theory of Capelli identities. We prove that this map provides a lower bound on the annihilators of theta lifts of representations with a fixed annihilator ideal. We also...