This paper presents two proof systems for the equivalence of programs. The language concerned is CLP to which the universal quantifier is added (CLPV). Both systems, axe based on first order classical logic. The first...
详细信息
ISBN:
(数字)9783540456193
ISBN:
(纸本)3540439307
This paper presents two proof systems for the equivalence of programs. The language concerned is CLP to which the universal quantifier is added (CLPV). Both systems, axe based on first order classical logic. The first uses an induction rule and allows one to prove that the set of finite successes of a program is included in another program's corresponding set. The second uses a coinduction rule for proving the inclusion of the sets of infinite successes which contain the finite successes. Finally we show that the proof systems axe equivalent under some natural conditions.
Most of the work conducted so far in the field of logic programming has focused on representing static knowledge, i.e., knowledge that does not evolve with time. To overcome this limitation, in a recent paper, the aut...
详细信息
ISBN:
(纸本)3540667490
Most of the work conducted so far in the field of logic programming has focused on representing static knowledge, i.e., knowledge that does not evolve with time. To overcome this limitation, in a recent paper, the authors introduced dynamic logic programming. There, they studied and defined the declarative and operational semantics of sequences of logic programs (or dynamic logic programs). Each program in the sequence contains knowledge about some given state, where different states may, for example, represent different time periods or different sets of priorities. But how, in concrete situations, is a sequence of logic programs built? For instance, in the domain of actions, what are the appropriate sequences of programs that represent the performed actions and their effects? Whereas dynamic logic programming provides a way for, given the sequence, determining what should follow, it does not provide a good practical language for the specification of the sequence of updates which may be conditional on the intervening states. Here we define the language LUPS-"Language for dynamic updates"-designed for specifying changes to logic programs. Given an initial knowledge base (as a logic program) LUPS provides a way for sequentially updating it. The declarative meaning of a sequence of sets of update actions in LUPS is defined by the semantics of the dynamic logic program generated by those actions. Additionally, we provide a translation of the sequence of update statements sets into a single logic program written in a meta-language, in such a way that the stable models of the resulting program correspond to the previously defined declarative semantics. Finally, we exhibit the usage of LUPS in several application domains. (C) 2002 Elsevier Science B.V. All rights reserved.
An approach concerning the applications of three-valued logics to knowledge-based systems is considered in the paper. The incompleteness of the scope is an existing fact, which leads in practice to the appearance of m...
详细信息
ISBN:
(纸本)0780376013
An approach concerning the applications of three-valued logics to knowledge-based systems is considered in the paper. The incompleteness of the scope is an existing fact, which leads in practice to the appearance of many difficulties and obstacles. One of the conclusions is that different probabilistic approaches could enlarge the problems instead of their simplification in the considered case. An exact estimation approach is elaborated that helps to avoid the use of probabilistic or relative esteems. It is based on juxtapositions, inheritance mechanisms and related inference tools. The material is illustrated by examples from different domains.
In a number of papers *** introduced algebras called bilattices having two separate lattice structure and one additional basic unary operation. They originated as an algebraization of some non-classical logics that ar...
详细信息
ISBN:
(纸本)3540003150
In a number of papers *** introduced algebras called bilattices having two separate lattice structure and one additional basic unary operation. They originated as an algebraization of some non-classical logics that arise in artificial intelligence and knowledge-based logic programming. In this paper we introduce some new class of bilattices which originate from interval lattices and show that each of them is simple. A known simple lattices are used to give other examples of simple bilattices. We also describe simple bilattices satisfying some additional identities so called P-bilattices (or interlaced bilattices).
We present a logic and logic programming based approach for analysing event-based requirements specifications given in terms of, a system's reaction to events and safety properties. The approach uses a variant of ...
详细信息
ISBN:
(数字)9783540456193
ISBN:
(纸本)3540439307
We present a logic and logic programming based approach for analysing event-based requirements specifications given in terms of, a system's reaction to events and safety properties. The approach uses a variant of Kowalski and Sergot's Event Calculus to represent such specifications declaratively and an abductive reasoning mechanism for analysing safety properties. Given a system description and a safety property, the abductive mechanism is able to identify a complete set of counterexamples (if any exist) of the property in terms of symbolic ''current" states and associated event-based transitions. A case study of an automobile cruise control system specified in the SCR framework is used to illustrate our approach. The technique described is implemented. using existing tools for abductive logic programming.
We propose an efficient operational semantics for a new class of rewrite systems, namely Timed Rewrite Systems. This class constitute a conservative extension of first-order conditional term rewrite systems together w...
详细信息
ISBN:
(纸本)0769514758
We propose an efficient operational semantics for a new class of rewrite systems, namely Timed Rewrite Systems. This class constitute a conservative extension of first-order conditional term rewrite systems together with time features such as clocks, signals, timed terms, timed atoms and timed rules. We define first Timed Rewrite Systems and illustrate them through some examples. A naive approach to the operational semantics is very costly in space. We propose, for a large class of programs, an improved calculus with a linear space complexity. Finally, we show how our framework compares to related work.
The aim of our ongoing research is to give a method to construct intelligent tutoring systems for agents who are executing typical procedures in dynamic environments based on a logical framework. Typical procedures ar...
详细信息
ISBN:
(纸本)0769518672
The aim of our ongoing research is to give a method to construct intelligent tutoring systems for agents who are executing typical procedures in dynamic environments based on a logical framework. Typical procedures are similar to plans in the sense that they describe the actions an agent should execute to achieve a certain goal. In this paper we address what we consider is the first step toward the construction of this kind of systems: procedure recognition. We formalize what does it mean that an agent is performing a procedure in the Situation Calculus [12], a logical first-order language extended with induction. Based upon this formalization, we give two different implementations. The first, which is directly based in our formalization, is proved to be quite inefficient. The second, significantly more efficient, arises from a logical reformulation of the original formalization. Procedures are represented through CON-GOLOG [6] programs, a logical interpreted language based on the Situation Calculus.
This paper shows how action theory in the language B can be naturally encoded using prioritized default theory. We also show how prioritized default theory can be extended to express preferences between rules and form...
详细信息
ISBN:
(纸本)3540441905
This paper shows how action theory in the language B can be naturally encoded using prioritized default theory. We also show how prioritized default theory can be extended to express preferences between rules and formulae. This extension provides a natural framework to introduce preferences over trajectories in B. We illustrate how these preferences can be expressed and how they can be represented within extended prioritized default theory. We also discuss how this framework can be implemented in terms of answer set programming.
The talk describes some of the formal foundations of Juno-2, a constraint-based graphical illustrator implemented by Allan Heydon and Greg Nelson and available over the web in source form. The first idea underlying Ju...
详细信息
ISBN:
(数字)9783540459880
ISBN:
(纸本)3540433813
The talk describes some of the formal foundations of Juno-2, a constraint-based graphical illustrator implemented by Allan Heydon and Greg Nelson and available over the web in source form. The first idea underlying Juno-2 is that constraint-based programming is obtained from ordinary imperative programming not by adding a feature but by subtracting a restriction: specifically by dropping the law of the excluded miracle from the calculus of guarded commands of Edsger W. Dijkstra. Dropping this law introduces "partial commands" (sometimes called "miracles"), which, when combined with conventional local variable introductions ("VAR statements") creates a highly principled constraint solving primitive that is beautifully orthogonal to the conventional imperative features of the language. The second idea is that the "combination of, decision procedures technique" that has been widely used in the automatic theorem-proving community for the last two decades can also be used to combine constraint solvers for two logical theories into a single constraint solver for the combination of the theories. Juno-2 uses this idea to combine a simple solver for the theory of a pairing function (which amounts only to an implementation of unification closure) with a sophisticated numerical solver for the theory of the real numbers to produce a powerful constraint solver that is useful for producing accurate technical illustrations and animations. The talk will include a demonstration of Juno-2, weather permitting.
We use the formal model for similarity-based fuzzy unification in multi-adjoint logic programs to provide new tools for flexible querying. Our approach is based on a general framework for logic programming, which give...
详细信息
ISBN:
(纸本)3540000747
We use the formal model for similarity-based fuzzy unification in multi-adjoint logic programs to provide new tools for flexible querying. Our approach is based on a general framework for logic programming, which gives a formal model of fuzzy logic programming extended by fuzzy similarities and axioms of first-order logic with equality. As a source of similarities we consider different approaches, such as statistical generation of fuzzy similarities, or similarities generated by some information retrieval techniques or similarities arising from fuzzy conceptual lattices.
暂无评论