The theory of perfect graphs relates the concept of graph colorings to the concept of cliques. In this paper, we introduce the concept of a perfect graph as well as a number of graph classes that are always perfect. We next introduce both theWeak Perfect Graph Theorem and the Strong Perfect Graph Theorem and provide a proof of the Weak Perfect Graph Theorem. We also demonstrate an application o...

We study the problem of encoding cardinality constraints (threshold functions) on Boolean variables into CNF. Specifically, we propose new encodings based on (perfect) hashing that are efficient in terms of the number of clauses, auxiliary variables, and propagation strength. We compare the properties of our encodings to known ones, and provide experimental results evaluating their practical ef...

This essay examines the use of famine-plot rhetoric in the course of disputes over free trade in the French Atlantic during the late eighteenth century. Seeking to discredit officially sanctioned trade monopolies, French plantation owners frequently suggested that the control exercised by metropolitan merchants over transatlantic commerce was responsible for food shortages among the enslaved po...

Four publications have demonstrated perfect timesharing of 1 simultaneous decisions. In all of these, (a). subjects were motivated to respond as quickly as possible, and with 1 exception that involved unusually extensive practice (E. Hazeltine, D. Teague, & R. B. Ivry, 2002, Experiment 4), (b). at least 1 of the 2 tasks was characterized by ideomotor (IM) compatibility, meaning that each task s...

Minimal perfect hash functions are used for memory efficient storage and fast retrieval of items from static sets. We present an infinite family of efficient and practical algorithms for generating minimal perfect hash functions which allow an arbitrary order to be specified for the keys. We show that almost all members of the family are space and time optimal, and we identify the one with mini...

The present research paper is an investigation of dark energy nature logarithmic $f(R, T)$-gravity cosmology in a flat FLRW space-time universe. We have derived modified Einstein's field equations for the function T)=R-16\pi G\alpha\ln(T)$ where $R$ Ricci scalar curvature, $T$ trace stress momentum tensor and $\alpha$ model parameter. solved form two fluid scenario as perfect-fluid dark-fluid, ...

By a theorem proved by Erdös, Kunen and Mauldin, for any nonempty perfect set P on the real line there exists a perfect set M of Lebesgue measure zero such that P +M = R. We prove a stronger version of this theorem in which the obtained perfect set M is a Dirichlet set. Using this result we show that the ideal of additive sets for any family generated by analytic subgroups of the reals contains...

Opinions differ on whether the readings in [1] are semantically distinct, or are pragmatic interpretations of a basic perfect meaning. The popular Reichenbachian theory of tense and aspect (Reichenbach 1947; important later studies include Comrie 1976, 1985, Dowty 1982, Partee 1984, Binnick 1991, Hornstein 1990, Kamp & Reyle 1993, Klein 1994) seems to force the latter view, for it provides an u...