A Note About Theory of Codes of Goppa

In this paper, we study about the theory of field of algebraic functions, a small introduction to theory of codes, highlighting at this point the study of geometric codes of Goppa, and some results involving the definition of floor of a divisor. This paper provides a quota for the minimum distance of a geometric code of Goppa. A such quota involve the floor of a divisor and provide a estimate for the minimum distance of this code.