On the number of correctable errors of the Feng-Rao decoding algorithm for AG codes

In this correspondence we give geometric codes on one of the curves of Garcia-Stichtenoth (1995) with the property that the true distances are bigger than Feng-Rao distances. Moreover, an example for which the Feng-Rao algorithm cannot correct more than [(d/sub FR/-1)/2]+1(<[(d/sub true/-1)/2]) errors is given.