Extremal graphs with no C4,s, or C10,s
Journal of Combinatorial Theory Series B
Linear-time encodable and decodable error-correcting codes
STOC '95 Proceedings of the twenty-seventh annual ACM symposium on Theory of computing
Computationally efficient error-correcting codes and holographic proofs
Computationally efficient error-correcting codes and holographic proofs
Sparse 0-1-matrices and forbidden hypergraphs
Proceedings of the ninth annual ACM-SIAM symposium on Discrete algorithms
Sparse Parity-Check Matrices over ${GF(q)}$
Combinatorics, Probability and Computing
Sparse parity-check matrices over finite fields
COCOON'03 Proceedings of the 9th annual international conference on Computing and combinatorics
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We consider the extremal problem to determine the maximalnumber N(m,k,r) of columns of a 0-1 matrix withm rows and at most r ones in each columnsuch that each k columns are linearly independentmodulo 2. For fixed integers k\geq 1and r≥ 1, we shall prove the probabilistic lowerbound N(m,k,r) = Ω (m^(kr/2(k-1))); for ka power of 2, we prove the upper bound N(m,k,r)=O(m^{\lceilkr/(k-1)\rceil /2}) which matches the lower bound forinfinitely many values of r. We give some explicitconstructions.