160 search results - page 21 / 32 » Homomorphism preservation theorems |
ICALP
2007
Springer
14 years 1 months ago
2007
Springer
We present algebraic conditions on constraint languages Γ that ensure the hardness of the constraint satisfaction problem CSP(Γ) for complexity classes L, NL, P, NP and ModpL. Th...
ICALP
2007
Springer
14 years 1 months ago
2007
Springer
Gaifman’s locality theorem states that every first-order sentence is equivalent to a local sentence. We show that there is no elementary bound on the length of the local sentenc...
JACM
2002
13 years 7 months ago
2002
We show how to use an interactive theorem prover, HOL, together with a model checker, SPIN, to prove key properties of distance vector routing protocols. We do three case studies: ...
ISLPED
2003
ACM
14 years 22 days ago
2003
ACM
Distributed wireless ad-hoc networks (DWANs) pose numerous technical challenges. Among them, two are widely considered as crucial: autonomous localized operation and minimization ...
QUESTA
2006
13 years 7 months ago
2006
So-called Whittle networks have recently been shown to give tight approximations for the performance of non-locally balanced networks with blocking, including practical routing pol...