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Reduction Orderings.
When we speak of an ordering we mean a total (or completable)
reduction ordering. A reduction ordering is a well-founded ordering on ground terms
that is compatible with contexts and is total or can be extended to
a total such ordering.
Reduction orderings are the basis for terminating computations
by term rewriting. Saturate provides several classes of reduction
orderings, including the lexicographic path ordering
and its AC-variant.
Orderings specify an orientation of binary atoms, in particular equalities,
indicating the preferred direction when replacing equals by equals.
A ordering also expresses preferences and directions
of search when attempting to construct models
for disjunctions: is to be viewed as , if ,
and this links ordered resolution to negation as failure in logic programming.
Harald Ganzinger
2002-12-04
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