Department of Computer Science | Institute of Theoretical Computer Science | CADMO

Theory of Combinatorial Algorithms

Prof. Emo Welzl and Prof. Bernd Gärtner

Finding The Sink Against The Devil

Towards The Peak - Problem Section

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Finding The Sink Against The Devil

presented by Komei Fukuda

Given any orientation we aim to find either a sink or a certificate that the orientation does not have the unique sink property. The certificate should be of polynomial size, e.g. two vertices v,w with out-map s(v),s(w), such that $(s(v)\oplus s(w))\cap(v\oplus w)=\emptyset$.

Denote by D(d) the minimal number of steps a deterministic algorithm would need for this problem and by t(d) the minimal number of steps a deterministic algorithm needs to find the sink in a unique sink orientation. It is obvious that $t(d)\leq D(d)$. For the dimensions 1,2 and 3 we have equality.



 


Ingo Schurr and Uli Wagner ({schurr,uli}@inf.ethz.ch)
2001-09-04