Immerman-Vardi theorem: Difference between revisions

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: '''Theorem (Immerman-Vardi)'''. Over finite, ordered structures, the queries expressible
: '''Theorem (Immerman-Vardi)'''. Over finite, ordered structures, the queries expressible in the logic FO(LFP) are precisely those that can be computed in polynomial time. Namely, FO(LFP) = P.
in the logic FO(LFP) are precisely those that can be computed in polynomial time. Namely, FO(LFP) = P.
 
* [I1986] N. Immerman, "[http://www.cs.umass.edu/~immerman/pub/query.pdf Relational queries computable in polynomial time]", Information and Control 68 (1986), 86-104
* [V1982] M. Vardi, Complexity of Relational Query Languages, 14th Symposium on Theory of Computation (1982), 137-146.

Revision as of 05:01, 10 August 2010

(More discussion needed!)

Theorem (Immerman-Vardi). Over finite, ordered structures, the queries expressible in the logic FO(LFP) are precisely those that can be computed in polynomial time. Namely, FO(LFP) = P.