author: | Sébastien Limet and Pierre Réty
|
title: | E-unification by means of tree tuple synchronized grammars |
keywords: | E-unification, narrowing, tree languages, decidability
|
abstract: | The goal of this paper is both to give an E-unification procedure that always terminates, and to decide unifiability.
For this, we assume that the equational theory is specified by a confluent
and constructor-based rewrite system, and that four additional restrictions
are satisfied. We give a procedure that represents the (possibly infinite)
set of solutions thanks to a tree tuple synchronized grammar, and that can
decide upon unifiability thanks to an emptiness test. Moreover, we show that
if only three of the four additional restrictions are satisfied then unifiability
is undecidable.
|
reference: |
Sébastien Limet and Pierre Réty
(1997),
E-unification by means of tree tuple synchronized grammars,
Discrete Mathematics and Theoretical Computer Science 1, pp. 69-98 |
ps.gz-source: | dm010105.ps.gz |
ps-source: | dm010105.ps ( 307 K
) |
pdf-source: | dm010105.pdf ( 391 K
) |