Muon-electron universality at high energies and hadronic corrections to $e^{+}e^{-}\rightarrow\mu^{+}\mu^{-}$

It is argued that unitarity and muon-electron universality are sufficient to determine the contribution of hadrons to the imaginary part of the forward amplitude for the process e/sup +/e/sup -/ to mu /sup +/ mu /sup -/. With these assumptions Im T/sub 1//sup h/(e/sup + /e/sup -/ to mu /sup +/ mu /sup -/)=s sigma (e/sup +/e/sup -/ to hadrons) to all orders in alpha . Some consequences of this formula are discussed. (4 refs).