  Integrated forms of the one-loop evolution equations are given for the Yukawa
couplings in the MSSM, valid for any value of $\tan \beta$, generalizable to
virtually any number of Yukawa fermions, and including all gauge couplings.
These forms turn out to have nice mathematical convergence properties which we
prove, and we determine the ensuing convergence criteria. Furthermore, they
allow to write down general sufficient and necessary conditions to avoid
singularities in the evolution of the Yukawa couplings over physically relevant
energy ranges. We also comment briefly on the possible use of these features
for physics issues and give a short numerical illustration.
