coding theory

Let C be a code of length n with respect to the channel (F", P) and let DMLD : F + C be a maximum likelihood decoder. (a) Show that the decoding error probability Perr(c) of c E C is given by Perr(e) (yle), C'EC\{c} yeY(c) where Y (c) = {y e Fn : Dmld(y) = c}. (b) Show that for every ce C we have the estimates Perr(c)