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Electronic Colloquium on Computational Complexity

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All reports by Author Don Coppersmith:

TR05-131 | 7th November 2005
Don Coppersmith, Lisa Fleischer, Atri Rudra

Ordering by weighted number of wins gives a good ranking for weighted tournaments

We consider the following simple algorithm for feedback arc set problem in weighted tournaments --- order the vertices by their weighted indegrees. We show that this algorithm has an approximation guarantee of $5$ if the weights satisfy \textit{probability constraints}
(for any pair of vertices $u$ and $v$, $w_{uv}+w_{vu}=1$). Special cases ... more >>>

TR05-104 | 16th September 2005
Don Coppersmith, Atri Rudra

On the Robust Testability of Product of Codes

Ben-Sasson and Sudan in~\cite{BS04} asked if the following test
is robust for the tensor product of a code with another code--
pick a row (or column) at random and check if the received word restricted to the picked row (or column) belongs to the corresponding code. Valiant showed that ... more >>>

TR04-052 | 14th June 2004
Michael Ben Or, Don Coppersmith, Michael Luby, Ronitt Rubinfeld

Non-Abelian Homomorphism Testing, and Distributions Close to their Self-Convolutions

In this paper, we study two questions related to
the problem of testing whether a function is close to a homomorphism.
For two finite groups $G,H$ (not necessarily Abelian),
an arbitrary map $f:G \rightarrow H$, and a parameter $0 < \epsilon <1$,
say that $f$ is $\epsilon$-close to a homomorphism ... more >>>

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