Small weight codewords in the codes arising from Desarguesian projective planes

We study codewords of small weight in the codes arising from Desarguesian projective planes. We first of all improve the results of K. Chouinard on codewords of small weight in the codes arising from PG(2, p), p prime. Chouinard characterized all the codewords up to weight 2p in these codes. Using a particular basis for this code, described by Moorhouse, we characterize all the codewords of weight up to 2p+ (p− 1)/2 if p ≥ 11. We then study the codes arising from PG(2, q = q 0). In particular, for q0 = p prime, p ≥ 7, we prove that the codes have no codewords with weight in the interval [q+2, 2q−1]. Finally, for the codes of PG(2, q), q = p, p prime, h ≥ 4, we present a discrete spectrum for the weights of codewords with weights in the interval [q + 2, 2q − 1]. In particular, we exclude all weights in the interval [3q/2, 2q − 1]. ∗This author’s research is supported by the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). †Supported by the Fund for Scientific Research Flanders (Belgium).