This paper presents a comprehensive approach for model-based diagnosis which includes proposals for characterizing and computing preferred diagnoses, assuming that the system description is augmented with a system structure (a directed graph explicating the interconnections between system components). Speciically, we rst introduce the notion of a consequence, which is a syntactically unconstrai...

‎in this paper we give a characterization for all commutative‎ ‎rings with $1$ whose zero-divisor graphs are $c_4$-free.‎

A tanglegram is a pair of trees on the same set of leaves with matching leaves in the two trees joined by an edge. Tanglegrams are widely used in computational biology to compare evolutionary histories of species. In this paper we present a formulation of two related combinatorial embedding problems concerning tanglegrams in terms of CNF-formulas. The first problem is known as planar embedding ...

Equations describing eigenmodes with the frequencies of the order of the geodesic acoustic frequency and the electron/ion diamagnetic frequency in toroidal plasmas are derived and analyzed, a code BOAS solving them is developed. It is shown that there exist drift-sound eigenmodes and new drift-Alfvén eigenmodes. This is done by means of an analytical consideration and numerical modelling of par...

For random CNF formulae with m clauses, n variables and an unrestricted number of literals per clause the transition from high to low satisfiability can be determined exactly for large n. The critical density m/n turns out to be strongly n-dependent, ccr ln(2)/(1-p) , where pn is the mean number of positive literals per clause.This is in contrast to restricted random SAT problems (random K-SAT...

The symmetry properties of mathematical structures are often important for understanding these structures. Graphs sometimes have a large group of symmetries, especially when they have an algebraic construction such as the Cayley graphs. These graphs are constructed from abstract groups and are vertex-transitive and this is the reason for their symmetric appearance. Some Cayley graphs have even ...

A new approach is presented for computing the interior medial axes of generic regions in R bounded by C-smooth parametric B-spline surfaces. The generic structure of the 3D medial axis is a set of smooth surfaces along with a singular set consisting of edge curves, branch curves, fin points and six junction points. In this work, the medial axis singular set is first computed directly from the B...

If L1 and L2 are linear equations, then the disjunctive Rado number of the set {L1, L2} is the least integer n, provided that it exists, such that for every 2-coloring of the set {1, 2, . . . , n} there exists a monochromatic solution to either L1 or L2. If such an integer n does not exist, then the disjunctive Rado number is infinite. In this paper, it is shown that for all integers a 1 and b ...

For a pair of given graphs we encode the isomorphism principle in the natural way as a CNF formula of polynomial size in the number of vertices, which is satisfiable if and only if the graphs are isomorphic. Using the CFI graphs from [12], we can transform any undirected graph G into a pair of non-isomorphic graphs. We prove that the resolution width of any refutation of the formula stating tha...

We study the complexity of various combinatorial problems when instances are speci ed using one of the following succinct speci cations: (1) the 1-dimensional nite periodic narrow speci cations (denoted 1-FPN-speci cations) of Ford et al. and Wanke [FF58, Wa93]; (2) the 1-dimensional nite periodic narrow speci cations with explicit boundary conditions (denoted 1-FPN(BC)-speci cations) of Gale [...