Weizmann Logo
Electronic Colloquium on Computational Complexity

Under the auspices of the Computational Complexity Foundation (CCF)

Login | Register | Classic Style

All reports by Author Lars Engebretsen:

TR02-053 | 20th July 2002
Lars Engebretsen, Venkatesan Guruswami

Is Constraint Satisfaction Over Two Variables Always Easy?

By the breakthrough work of HÃ¥stad, several constraint satisfaction
problems are now known to have the following approximation resistance
property: satisfying more clauses than what picking a random
assignment would achieve is NP-hard. This is the case for example for
Max E3-Sat, Max E3-Lin and Max E4-Set Splitting. A notable ... more >>>

TR02-040 | 20th June 2002
Lars Engebretsen, Jonas Holmerin

Three-Query PCPs with Perfect Completeness over non-Boolean Domains

We study non-Boolean PCPs that have perfect completeness and read
three positions from the proof. For the case when the proof consists
of values from a domain of size d for some integer constant d
>= 2, we construct a non-adaptive PCP with perfect completeness
more >>>

TR02-030 | 3rd June 2002
Lars Engebretsen, Jonas Holmerin, Alexander Russell

Inapproximability Results for Equations over Finite Groups

Revisions: 1

An equation over a finite group G is an expression of form
w_1 w_2...w_k = 1_G, where each w_i is a variable, an inverted
variable, or a constant from G; such an equation is satisfiable
if there is a setting of the variables to values in G ... more >>>

TR00-089 | 1st December 2000
Lars Engebretsen, Marek Karpinski

Approximation Hardness of TSP with Bounded Metrics

Revisions: 1

The general asymmetric (and metric) TSP is known to be approximable
only to within an O(log n) factor, and is also known to be
approximable within a constant factor as soon as the metric is
bounded. In this paper we study the asymmetric and symmetric TSP
problems with bounded metrics ... more >>>

TR00-042 | 21st June 2000
Lars Engebretsen

Lower Bounds for non-Boolean Constraint Satisfaction

Revisions: 1

We show that the k-CSP problem over a finite Abelian group G
cannot be approximated within |G|^{k-O(sqrt{k})}-epsilon, for
any constant epsilon>0, unless P=NP. This lower bound matches
well with the best known upper bound, |G|^{k-1}, of Serna,
Trevisan and Xhafa. The proof uses a combination of PCP
techniques---most notably a ... more >>>

ISSN 1433-8092 | Imprint