Tomislav J. Šagi – Bunić i Bonaventura Duda

THE CONCEPT OF (I; J)-COHEN MACAULAY MODULES

‎We introduce a generalization of the notion of‎ depth of an ideal on a module by applying the concept of‎ local cohomology modules with respect to a pair‎ ‎of ideals‎. ‎We also introduce the concept of $(I,J)$-Cohen--Macaulay modules as a generalization of concept of Cohen--Macaulay modules‎. ‎These kind of modules are different from Cohen--Macaulay modules‎, as an example shows‎. ‎Also an art...

(i, J) Competition Graphs

Hefner, K.A.S., K.F. Jones, S. Kim, J.R. Lundgren and F.S. Roberts, (i,j) competition graphs, Discrete Applied Mathematics 32 (1991) 241-262. If D is an acyclic digraph, its competition graph has the same vertex set as D and an edge between vertices x and y if and only if for some vertex u, there are arcs (_q u) and (_Y, u) in D. We study competition graphs of acyclic digraphs D when the indegr...

I T L:  J

We discuss a family of modal logics for reasoning about relational structures of intervals over (usually) linear orders, with modal operators associated with the various binary relations between such intervals, known as Allen’s interval relations. The formulae of these logics are evaluated at intervals rather than points and the main effect of that semantic feature is substantially higher expre...

On the matrix equations U_iXV_j W_{i j} for 1 \leq i; j \leq k with i +j \leq k

In between k -Sets, j -Facets, and i -Faces: (i , j) - Partitions

Let S be a finite set of points in general position in Rd. We call a pair (A,B) of subsets of S an (i, j)-partition of S, if |A| = i, |B| = j and there is an oriented hyperplane h with S∩h = A and with B the set of points from S on the positive side of h. (i, j)-Partitions generalize the notions of k-sets (these are (0, k)-partitions) and j-facets ((d, j)-partitions) of point sets as well as th...