The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform

Michael Beeson - One of the best experts on this subject based on the ideXlab platform.

Vladimir V. Rybakov - One of the best experts on this subject based on the ideXlab platform.

  • Writing out Unifiers in Linear Temporal Logic
    Journal of Logic and Computation, 2011
    Co-Authors: Vladimir V. Rybakov
    Abstract:

    We solve unification problem for linear temporal logic (LTL). For any given formula φ, we verify if φ is unifiable in LTL; if yes, we construct its unfolded form; and, next, by this form we directly write out the most General Unifier for φ. Thus, we show any unifiable in LTL formula has a most General Unifier (thus, LTL enjoys unitary unification), though we also show that there are unifiable in LTL formulas which are not projective.

  • KES (2) - Chance discovery and unification in linear modal logic
    Knowlege-Based and Intelligent Information and Engineering Systems, 2011
    Co-Authors: Vladimir V. Rybakov
    Abstract:

    This paper studies an interpretation of the Chance Discovery (CD) as the unification problem in the linear modal logic S4.3. We prove that any formula unifiable in S4.3 has a most General Unifier, and we give an algorithm which, for any unifiable formula, constructs a most General Unifier. More precisely, we merely write out, explicitly, the formulas giving substitutions for a most-General Unifier. From computational viewpoint, we find an algorithm for the construction of sets of 'best Unifiers' (complete collections of 'most' General Unifiers) in the linear modal logic S4.3.

  • Unification in linear temporal logic LTL
    Annals of Pure and Applied Logic, 2011
    Co-Authors: Sergey Babenyshev, Vladimir V. Rybakov
    Abstract:

    Abstract We prove that a propositional Linear Temporal Logic with Until and Next (LTL) has unitary unification. Moreover, for every unifiable in LTL formula A there is a most General projective Unifier, corresponding to some projective formula B, such that A is derivable from B in LTL. On the other hand, it can be shown that not every open and unifiable in LTL formula is projective. We also present an algorithm for constructing a most General Unifier.

Christian Prehofer - One of the best experts on this subject based on the ideXlab platform.

  • JELIA - An Efficient Constraint Language for Polymorphic Order-sorted Resoluton
    Lecture Notes in Computer Science, 1
    Co-Authors: Christian Prehofer
    Abstract:

    In recent years various sorted logics have been developed, mostly to facilitate knowledge representation and to speed up automated deduction. We present a polymorphic order-sorted logic that can be implemented efficiently. Because the polymorphism is almost unrestricted, it is possible for two terms to have an exponential number of maximally General Unifiers. To guarantee a single most General Unifier, we embed the sorted logic into a more General constraint logic and create a distinct constraint satisfaction search space. This separates the total search space into two orthogonal ones and facilitates many optimizations. The main complexity gains are that the unnecessary generation of Unifiers can be avoided and that the primary resolution search space remains constant if the complexity of the unification grows.

Gérard P. Huet - One of the best experts on this subject based on the ideXlab platform.

Vasco T. Vasconcelos - One of the best experts on this subject based on the ideXlab platform.

  • Unification of kinded infinite trees
    Information Processing Letters, 1995
    Co-Authors: Vasco T. Vasconcelos
    Abstract:

    We study the problem of unifying infinite trees with variables subject to constraints on the trees they may be substituted for. The constraints are given by mappings from variables to trees, called kindings. In particular, we show that if a set of equations over a given kinding is unifiable, it has a most General Unifier using only a subset of the variables in the set of equations and in the kinding. We present an efficient algorithm to extract the most General Unifier of a regular (having a finite number of subtrees) and unifiable set of equations over a given kinding. The results extend those of Huet on unification of regular trees, and those of Ohori on unification of kinded finite trees.