# A solved form algorithm for ask and tell Herbrand constraints

CAAP Colloquium On Trees In Algebra And Programming

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## Abstract

We consider the problem of defining a solved form for ask and tell equalities over the Herbrand universe used as semantic domain of concurrent constraint programs. We give a solved form which is unique up to renaming for equivalent constraints, and we show an algorithm to compute it. The solved form and the related algorithm are extended to reactive trees consisting of ask and tell constraints. The algorithms are finally shown to be correct, i.e. to preserve the semantics of ask and tell constraints and of reactive trees.

## Keywords

Logic Program Reactive Sequence Logic Programming Reactive Tree Constraint Logic Programming
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© Springer-Verlag Berlin Heidelberg 1991