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The reaction e ϩ e Ϫ → ϩ Ϫ has been measured at ͱsϭ57.77 GeV, based on 289.6Ϯ2.6 pb Ϫ1 data collected with the VENUS detector at TRISTAN. The production cross section is measured in bins of the production angle within an angular acceptance of ͉cos ͉р0.75, according to a model-independent definition. The result is consistent with the prediction of the standard electroweak theory. Although a trend in measurements at lower energies that the total cross section tends to be smaller than the prediction remains, the discrepancy is not significant. The model-independent result is converted to the differential cross section in the effective-Born scheme by unfolding photon-radiation effects. This result can be extrapolated to quantities for the full solid angle as tot EB ϭ30.05Ϯ0.59 pb and A FB EB ϭϪ0.350Ϯ0.017, by imposing an ordinary assumption on the production-angle dependence. The converted results are used to set constraints on extensions of the standard theory. S-matrix parametrization, and possible contributions from contact interactions and heavy neutral-scalar exchanges are examined. ͓S0556-2821͑98͒04309-4͔