  The proton's transversity distribution will be measured at BNL's Relativistic
Heavy Ion Collider in upcoming experiments using the transverse Drell-Yan
process. Understanding the one-loop corrections is therefore important. Here,
the collinear structure in transverse Drell-Yan is investigated in detail using
dimensional regularization and the correct behaviour is found, although the
mechanism is non-trivial. The resulting n-dimensional transversity splitting
function (and consequently the one-loop transversity distribution and its
two-loop evolution) is found to be the same in both the anticommuting-gamma_5
scheme and the HVBM scheme. Alternative schemes are considered.
