Linear codes from projective spaces

The linear code Cs,t(n, q) of s-spaces and t-spaces in a projective space PG(n, q), q = ph, p prime, is defined as the vector space spanned over Fp by the rows of the incidence matrix of s-spaces and t-spaces. This code generalises the code of points and lines in a projective plane, which has been intensively studied since the 1970’s. In this paper, we give an overview of what is currently known about the codes Cs,t(n, q) and their duals.