Cancellation of one-loop divergences in SO(8192) string theory

It is shown that the usual one-loop divergence is absent in SO(8192) open bosonic string theory in 26 dimensions, for which the dilaton tadpole is known to cancel. To obtain this result, it is necessary to perform an appropriate analytic continuation to eliminate the apparent divergence from the closed-string tachyon tadpole. Using this approach, the dilaton tadpole is calculated for general open bosonic string theories, with results in agreement (nearly) with those obtained by other methods. (orig.)