20 search results - page 3 / 4 » Characterization of Context-Free Languages with Polynomially... |
PODS
1997
ACM
13 years 10 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...
LATA
2009
Springer
14 years 16 days 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
13 years 11 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
13 years 10 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...
ALT
1995
Springer
13 years 9 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...