20 search results - page 3 / 4 » Characterization of Context-Free Languages with Polynomially... |
PODS
1997
ACM
15 years 3 months ago
1997
ACM
We rework parts of the classical relational theory when the underlying domain is a structure with some interpreted operations that can be used in queries. We identify parts of the...
110
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LATA
2009
Springer
15 years 6 months ago
2009
Springer
Abstract. Motivated by strong Karp-Lipton collapse results in bounded arithmetic, Cook and Kraj´ıˇcek [7] have recently introduced the notion of propositional proof systems with...
FOCS
2003
IEEE
15 years 4 months ago
2003
IEEE
We give a complexity theoretic classification of homomorphism problems for graphs and, more generally, relational structures obtained by restricting the left hand side structure ...
LATA
2009
Springer
15 years 4 months ago
2009
Springer
Abstract. This paper contributes to the study of Freely Rewriting Restarting Automata (FRR-automata) and Parallel Communicating Grammar Systems (PCGS) as formalizations of the ling...
106
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ALT
1995
Springer
15 years 3 months ago
1995
Springer
This paper characterizes the polynomial time learnability of TPk, the class of collections of at most k rst-order terms. A collection in TPk de nes the union of the languages de n...