The valuations of the near polygon G.
We study the functional codes defined on a projective algebraic variety , in the case where is a non-degenerate Hermitian surface. We first give some bounds for , which are better than the ones known. We compute the number of codewords reaching the second weight. We also estimate the third weight, show the geometrical structure of the codewords reaching this third weight and compute their number. The paper ends with a conjecture on the fourth weight and the fifth weight of the code .
A set of lines of is said to cover a point of times if there are exactly lines of incident with . An -cover of is a set of lines of which covers each point of times. In this paper, the properties and known examples of -covers...