Tools
Sorted by:
Try your query at:
 |
 |
 |
 |
 |
 |
Results 1 - 10
of
137
Ricci Flow with Surgery on Three-Manifolds
"... This is a technical paper, which is a continuation of [I]. Here we verify most of the assertions, made in [I, §13]; the exceptions are (1) the statement that a 3-manifold which collapses with local lower bound for sectional curvature is a graph manifold- this is deferred to a separate paper, as the ..."
Abstract
-
Cited by 448 (2 self)
- Add to MetaCart
, as the proof has nothing to do with the Ricci flow, and (2) the claim about the lower bound for the volumes of the maximal horns and the smoothness of the solution from some time on, which turned out to be unjustified, and, on the other hand, irrelevant for the other conclusions. The Ricci flow with surgery
On the Maximal Models of Horn Formulas
, 1998
"... We investigate the problem of generating the maximal models of Horn formulas. Based on the Resolution Theorem of Kavvadias and Stavropoulos [Computer Technology Institute, CTI TR 98.2.4, February 1998], the generation of the maximal models of a Horn formula with constant number of variables with pos ..."
Abstract
-
Cited by 2 (1 self)
- Add to MetaCart
We investigate the problem of generating the maximal models of Horn formulas. Based on the Resolution Theorem of Kavvadias and Stavropoulos [Computer Technology Institute, CTI TR 98.2.4, February 1998], the generation of the maximal models of a Horn formula with constant number of variables
Reasoning about Temporal Relations: A Maximal Tractable Subclass of Allen's Interval Algebra
- Journal of the ACM
, 1995
"... We introduce a new subclass of Allen's interval algebra we call "ORDHorn subclass," which is a strict superset of the "pointisable subclass." We prove that reasoning in the ORD-Horn subclass is a polynomial-time problem and show that the path-consistency method is sufficient ..."
Abstract
-
Cited by 199 (9 self)
- Add to MetaCart
is sufficient for deciding satisfiability. Further, using an extensive machine-generated case analysis, we show that the ORD-Horn subclass is a maximal tractable subclass of the full algebra (assuming<F NaN> P6=NP). In fact, it is the unique greatest tractable subclass amongst the subclasses that contain
Disjunction of Horn theories and their cores
, 1999
"... . In this paper, we study issues on disjunctions of propositional Horn theories. In particular, we consider deciding whether a disjunction of Horn theories is Horn, and, if not, computing a Horn core (i.e., a maximal Horn theory included in this disjunction) and Horn envelope (i.e., the minimum Horn ..."
Abstract
- Add to MetaCart
. In this paper, we study issues on disjunctions of propositional Horn theories. In particular, we consider deciding whether a disjunction of Horn theories is Horn, and, if not, computing a Horn core (i.e., a maximal Horn theory included in this disjunction) and Horn envelope (i.e., the minimum
A maximal-literal unit strategy for Horn clauses
- In Proc. CTRS-90
, 1991
"... A new positive-unit theorem-proving procedure for equational Horn clauses is presented. It uses a term ordering to restrict paxamodulation to potentially maximal sides of equations. Completeness is shown using proof orderings. 1. ..."
Abstract
-
Cited by 13 (0 self)
- Add to MetaCart
A new positive-unit theorem-proving procedure for equational Horn clauses is presented. It uses a term ordering to restrict paxamodulation to potentially maximal sides of equations. Completeness is shown using proof orderings. 1.
Disjunctions of Horn Theories and their Cores
, 2001
"... In this paper, we study issues on disjunctions of propositional Horn theories. In particular, we consider the problems of deciding whether a disjunction of Horn theories is Horn, and, if not, computing a Horn core (i.e., a maximal Horn theory included in this disjunction) and the Horn envelope (i ..."
Abstract
-
Cited by 3 (2 self)
- Add to MetaCart
In this paper, we study issues on disjunctions of propositional Horn theories. In particular, we consider the problems of deciding whether a disjunction of Horn theories is Horn, and, if not, computing a Horn core (i.e., a maximal Horn theory included in this disjunction) and the Horn envelope
Learning Useful Horn Approximations
- In Proceedings of the International Conference on the Principles of Knowledge Representation and Reasoning
, 1992
"... While the task of answering queries from an arbitrary propositional theory is intractable in general, it can typically be performed efficiently if the theory is Horn. This suggests that it may be more efficient to answer queries using a "Horn approximation"; i.e., a horn theory that is sem ..."
Abstract
-
Cited by 17 (6 self)
- Add to MetaCart
While the task of answering queries from an arbitrary propositional theory is intractable in general, it can typically be performed efficiently if the theory is Horn. This suggests that it may be more efficient to answer queries using a "Horn approximation"; i.e., a horn theory
An Algorithm for Enumerating Maximal Models of Horn Theories with an Application to Modal Logics ⋆
"... Abstract. The fragment of propositional logic known as Horn theories plays a central role in automated reasoning. The problem of enumerating the maximal models of a Horn theory (MaxMod) has been proved to be computationally hard, unless P = NP. To the best of our knowledge, the only algorithm availa ..."
Abstract
-
Cited by 2 (2 self)
- Add to MetaCart
Abstract. The fragment of propositional logic known as Horn theories plays a central role in automated reasoning. The problem of enumerating the maximal models of a Horn theory (MaxMod) has been proved to be computationally hard, unless P = NP. To the best of our knowledge, the only algorithm
Combinatorial problems for Horn clauses
, 2007
"... Given a family of Horn clauses, what is the minimal number of Horn clauses implying all other clauses in the family? What is the maximal number of Horn clauses from the family without having resolvents of a certain kind? We consider various problems of this type, and give some sharp bounds. We also ..."
Abstract
- Add to MetaCart
Given a family of Horn clauses, what is the minimal number of Horn clauses implying all other clauses in the family? What is the maximal number of Horn clauses from the family without having resolvents of a certain kind? We consider various problems of this type, and give some sharp bounds. We also
Ordering-Based Strategies for Horn Clauses
, 1991
"... Two new theorem-proving procedures for equational Horn clauses are presented. The largest literal is selected for paramodulation in both strategies, except that one method treats positive literals as larger than negative ones and results in a unit strategy. Both use term orderings to restrict paramo ..."
Abstract
-
Cited by 12 (4 self)
- Add to MetaCart
Two new theorem-proving procedures for equational Horn clauses are presented. The largest literal is selected for paramodulation in both strategies, except that one method treats positive literals as larger than negative ones and results in a unit strategy. Both use term orderings to restrict
Results 1 - 10
of
137
