In recent years, the description logic EL has received a significant interest. The description logic EL is a knowledge representation formalism used e.g in natural language processing, configuration of technical systems, databases and biomedical ontologies. Unification is used there as a tool to recognize equivalent concepts. It has been proven that unification in EL is NP-complete. This result...

Rigid E -unification is the problem of unifying two expressions modulo a set of equations, with the assumption that every variable denotes exactly one term (rigid semantics). This form of unification was originally developed as an approach to integrate equational reasoning in tableau-like proof procedures, and studied extensively in the late 80s and 90s. However, the fact that simultaneous rigi...

Unification of disjunctive feature descriptions is important for efficient unification-based parsing. This paper presents constraint projection, a new method for unification of disjunctive feature structures represented by logical constraints. Constraint projection is a generalization of constraint unification, and is more efficient because constraint projection has a mechanism for abandoning i...

We extend first-order order-sorted unification by permitting regular expression sorts for variables and in the domains of function symbols. The set of basic sorts is finite. The corresponding unification problem is infinitary. We conjecture that this unification problem is decidable and give a complete unification procedure.

We consider unification of terms under the equational theory of two-sided distributivity D with the axioms x*(y+z) = x*y + x*z and (x+y)*z = x*z + y*z. The main result of this paper is that Dunification is decidable by giving a non-deterministic transformation algorithm. The generated unification are: an AC1-problem with linear constant restrictions and a second-order unification problem that c...

the world of law has been dominated by waves of codification or re-codification and by currents of harmonization and unification. innumerable institutions, not only in europe but around the globe including in iran, try to bring legal systems together, and to suggest uniform laws. such attempts necessarily rely on comparative law as the first methodological tool. the european experience is an il...

Summary The people of the two Koreas cannot communicate directly with one another. Since early 1990s, South and North Korea have allowed a limited number people-to-people exchanges. In this article, we map Korean government’s theories change regarding inter-Korean exchanges based on policy documents semi-structured interviews five high-level Ministry Unification bureaucrats. We also explore out...