Gérard Cohen

Binary B_2-Sequences: a new upper bound (2007)

Gérard Cohen, Simon Litsyn

We show that the maximum size of a B_2-sequence of binary n-vectors for large enough n is at most 2^0.5753n, thus improving on the previous bound 2^0.6n due to B. Lindström.

A hypergraph approach to the identifying parent property: the case of multiple parents (2001)

Alexander Barg, Gérard Cohen, Sylvia Encheva

GREGORY KABATIANSKY ¶ , AND GILLES ZÉMOR � Abstract. Let C be a code of length n over analphabet of q letters. An n-word y is called a descendant of a set of t codewords x1,...,xt if yi ∈{x1...

Antichain Codes (1999)

Gérard Cohen, G#rard D. Cohen, Gilles Zémor, Sylvia B. Encheva

Introduction A binary vector x is identiøed with its support, the set of its non-zero coordinate positions. Logarithms are binary. We consider binary linear codes C[n; k; d] with weight hierarchy fd...

How to Improve an Exponentiation Black-Box (1998)

Gérard Cohen, Antoine Lobstein, David Naccache

this paper we present a method for improving the performance of RSA-type exponentiations. The scheme is based on the observation that replacing the exponent d by d

How to Improve an Exponentiation Black-Box (1998)

Published In Nyberg, Gérard Cohen, Antoine Lobstein, David Naccache, Gilles Zémor, Gemplus Card International

In this paper we present a method for improving the performance of RSA-type exponentiations. The scheme is based on the observation that replacing the exponent d by d # = d + k#(n) has no arithmetic...

On the Traveling Salesman Problem in Binary Hamming Spaces (1996)

Gérard Cohen, Simon Litsyn, Gilles Zémor, Gilles Z Emor

Given a subset X of vertices in the n-cube, i.e. the n-dimensional Hamming space, we are interested in the solution for the traveling salesman problem, namely the minimal length of a cycle passing...

On Greedy Algorithms in Coding Theory (1996)

Gérard Cohen, Simon Litsyn, Gilles Zémor, Gilles Z'emor

We study a wide class of problems in coding theory for which we consider two different formulations: in terms of incidence matrices and in terms of hypergraphs. These problems are dealt with using a...