abstract the oak leafroller moth , tortrix viridana l. is a destructive pest within it’s spreading area which invades the oak species, especially in west and northwest forests of iran, in recent years. some parts of west azarbayjan’s forests which are located in piranshahr and sardasht region have been affected by this pest since 1989 that oak trees vigor and survival have been gone down result...

We prove that for any fixed r ≥ 2, the tree-width of graphs not containing Kr as a topological minor (resp. as a subgraph) is bounded by a linear (resp. polynomial) function of their rank-width. We also present refinements of our bounds for other graph classes such as Kr-minor free graphs and graphs of bounded genus.

Disjunctive Answer Set Programming (ASP) is a powerful declarative programming paradigm whose main decision problems are located on the second level of the polynomial hierarchy. Identifying tractable fragments and developing efficient algorithms for such fragments are thus important objectives in order to complement the sophisticated ASP systems available to date. Hard problems can become tract...

Tree-width and clique-width are two important graph complexity measures that serve as parameters in many fixed-parameter tractable (FPT) algorithms. The same classes of sparse graphs, in particular of planar graphs and of graphs of bounded degree have bounded tree-width and bounded clique-width. We prove that, for sparse graphs, clique-width is polynomially bounded in terms of tree-width. For p...

PETR HLINĚNÝ1,2,*, SANG-IL OUM3,7, DETLEF SEESE4 AND GEORG GOTTLOB5,6 Faculty of Informatics, Masaryk University, Botanická 68a, 602 00 Brno, Czech Republic VŠB, Technical University of Ostrava, Ostrava, Czech Republic School of Mathematics, Georgia Institute of Technology, Atlanta, GA 30332-0160, USA Institute AIFB, University Karlsruhe (TH), D-76128 Karlsruhe, Germany Oxford University Comput...

We give a simple proof that the straightforward generalisation of clique-width to arbitrary structures can be unbounded on structures of bounded tree-width. This can be corrected by allowing fusion of elements.

We show that for every forest T the linear rank-width of T is equal to the path-width of T , and the linear clique-width of T equals the path-width of T plus two, provided that T contains a path of length three. It follows that both linear rank-width and linear clique-width of forests can be computed in linear time. Using our characterization of linear rank-width of forests, we determine the se...

The width of a subset C of the vertices of a distance-regular graph is the maximum distance which occurs between elements of C. Dually, the dual width of a subset in a cometric association scheme is the index of the “last” eigenspace in the Q-polynomial ordering to which the characteristic vector of C is not orthogonal. Elementary bounds are derived on these two new parameters. We show that any...

There are several reasons why this book might be of interest to a TEX user. First, LTEX has a prominent place in the book. Second, the book describes a very interesting offshoot of literate programming, a topic traditionally popular in the TEX community. Third, since a number of TEX users work with data analysis and statistics, R could be a useful tool for them. Since some TUGboat readers are l...