By using results and techniques from commutative algebra such as the vanish
ing ideal of a set of points, its a-invariant, the Hilbert polynomial and s
eries, as well as finite free resolutions and the canonical module, some re
sults about Reed-Muller codes defined on a zero-dimensional complete inters
ection in the n-projective dimensional space are given. Several examples of
this class of codes are presented in order to illustrate the ideas.