On Finding Solutions for Extended Horn Formulas
نویسندگان
چکیده
In this note we present a simple quadratic-time algorithm for solving the satissability problem for a special class of boolean formulas. This class properly contains the class of extended Horn formulas 1] and balanced formulas 2, 4]. Previous algorithms for these classes require testing membership in the classes. However, the problem of recognizing balanced formulas is complex, and the problem of recognizing extended Horn formulas is not known to be solvable in polynomial time. Our algorithm requires no such test for membership.
منابع مشابه
Fault Tolerant Boolean Satisfiability
A δ-model is a satisfying assignment of a Boolean formula for which any small alteration, such as a single bit flip, can be repaired by flips to some small number of other bits, yielding a new satisfying assignment. These satisfying assignments represent robust solutions to optimization problems (e.g., scheduling) where it is possible to recover from unforeseen events (e.g., a resource becoming...
متن کاملTranslating propositional extended conjunctions of Horn clauses into Boolean circuits
Horn is a logic programming language which extends usual Horn clauses by adding intuitionistic implication in goals and clause bodies. This extension can be seen as a form of structuring programs in logic programming. We are interested in finding correct and efficient translations from Horn⊃ programs into some representation type that, preserving the signature, allow us suitable implementations...
متن کاملFinding Tractable Formulas in NNF
Many applications in Computer Science require to represent knowledge and to reason with non normal form formulas. However, most of the advances in tractable reasoning are applied only to CNF formulas. In this paper, we extend tractability to several classes of non normal formulas which are of high practical interest. Thus, we rst deene three non normal Horn-like classes of formulas F1 ^ F2 ^ : ...
متن کاملApplication of the new extended (G'/G) -expansion method to find exact solutions for nonlinear partial differential equation
In recent years, numerous approaches have been utilized for finding the exact solutions to nonlinear partial differential equations. One such method is known as the new extended (G'/G)-expansion method and was proposed by Roshid et al. In this paper, we apply this method and achieve exact solutions to nonlinear partial differential equations (NLPDEs), namely the Benjamin-Ono equation. It is est...
متن کاملA perspective on certain polynomial-time solvable classes of satisfiability
The scope of certain well-studied polynomial-time solvable classes of Satisfiability is investigated relative to a polynomial-time solvable class consisting of what we call matched formulas. The class of matched formulas has not been studied in the literature, probably because it seems not to contain many challenging formulas. Yet, we find that, in some sense, the matched formulas are more nume...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Inf. Process. Lett.
دوره 54 شماره
صفحات -
تاریخ انتشار 1995