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What and Who

Hitting sets when the VC-dimension is small

Guy Even
Tel-Aviv University
Course
AG 1, AG 2, AG 3, AG 4, AG 5  
AG Audience
English

Date, Time and Location

Tuesday, 3 August 2004
13:30
120 Minutes
46.1 - MPII
024
Saarbrücken

Abstract

The Hitting Set Problem is NP-Complete and it is even NP-Complete to

approximate with a ratio of $c\log m$, for some constant c, where m is the
number of sets in the set system.

Broennimann & Goodrich showed that an $O(\log(OPT))$ approximation ratio
is achievable in polynomial time if the VC-dimension of the set system is
constant. Moreover, their algorithm achieves a constant approximation
ratio if the set system admits $\epsilon$-nets of size $O(1/\epsilon)$.

I will start this talk by defining the relevant terms (e.g.,
VC-dimension and $\epsilon$-nets), presenting the main theorems, and
discussing a few examples from Matousek's book on Discrete Geometry. I
will then present a simple approximation algorithm that builds on
Pach & Agarwal. This algorithm only requires (approximately) solving a
hitting set linear program and finding one $\epsilon$-net.

A few extensions will be mentioned, such as: parallelization and
dealing with the min-cost hitting set problem.

Joint work with Dror Rawitz and Moni Shahar.

Contact

Martin Skutella
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Martin Skutella, 07/27/2004 12:31
Martin Skutella, 07/14/2004 12:03 -- Created document.