Abstract:
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Different relationships between single-pushout rewriting of total and
partial unary algebras are studied in this paper. In general, given a
single-pushout transformation rule r of total algebras, a
corresponding single-pushout transformation rule r' of partial
algebras can be found such that single-pushout derivations by the
application of r are epireflections of single-pushout derivations
by the application of r' But, unlike the case of double-pushout
derivations, in this case single-pushout transformation rules of partial
algebras become "larger" than corresponding rules of total algebras.
Therefore, ad hoc methods are developed to compute pushouts of
partial homomorphisms through free completions which, in the case of
hypergraphs, may lead to a slight improvement in efficiency of
pattern-matching and to a moderate improvement in efficiency of
single-pushout transformations. |