Minimal forbidden sets for degree sequence characterizations

Minimal forbidden sets for degree sequence characterizations

Given a set F of graphs, a graph G is F-free if G does not contain any member of F as an induced subgraph. Barrus, Kumbhat, and Hartke [4] called F a degree-sequence-forcing (DSF) set if, for each graph G in the class C of F-free graphs, every realization of the degree sequence of G is also in C. A DSF set is minimal if no proper subset is also DSF. In this paper, we present new properties of m...

Enumeration of Circuits and Minimal Forbidden Sets

On minimal forbidden subgraph characterizations of balanced graphs

A graph is balanced if its clique-matrix contains no edge-vertex incidence matrix of an odd chordless cycle as a submatrix. While a forbidden induced subgraph characterization of balanced graphs is known, there is no such characterization by minimal forbidden induced subgraphs. In this work, we provide minimal forbidden induced subgraph characterizations of balanced graphs restricted to graphs ...

On the generation of circuits and minimal forbidden sets

We present several complexity results related to generation and counting of all circuits of an independence system. Our motivation to study these problems is their relevance in the solution of resource constrained scheduling problems, where an independence system arises as the subsets of jobs that may be scheduled simultaneously. We are interested in the circuits of this system, the so-called m...

Rational curves of minimal degree and characterizations of Pn

In this paper we investigate complex uniruled varieties X whose rational curves of minimal degree satisfy a special property. Namely, we assume that the tangent directions to such curves at a general point x ∈ X form a linear subspace of TxX. As an application of our main result, we give a unified geometric proof of Mori’s, Wahl’s, Campana-Peternell’s and Andreatta-Wísniewski’s characterization...