## Interaction between Path and Type Constraints (1999)

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Venue: | In Proceedings of ACM Symposium on Principles of Database Systems (PODS |

Citations: | 35 - 15 self |

### BibTeX

@INPROCEEDINGS{Buneman99interactionbetween,

author = {Peter Buneman and Wenfei Fan and Scott Weinstein},

title = {Interaction between Path and Type Constraints},

booktitle = {In Proceedings of ACM Symposium on Principles of Database Systems (PODS},

year = {1999},

pages = {56--67}

}

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### Abstract

This paper investigates that interaction. In particular it studies constraint implication problems, which are important both in understanding the semantics of type/constraint systems and in query optimization. It shows that path constraints interact with types in a highly intricate way. For that purpose a number of results on path constraint implication are established in the presence and absence of type systems. These results demonstrate that adding a type system may in some cases simplify reasoning about path constraints and in other cases make it harder. For example, it is shown that there is a path constraint implication problem that is decidable in PTIME in the untyped context, but that becomes undecidable when a type system is added. On the other hand, there is an implication problem that is undecidable in the untyped context, but becomes not only decidable in cubic time but also finitely axiomatizable when a type system is imposed