We understand that visiting students do not have formal prerequisites satisfied in most cases, and so we are happy to work with these students on enrollment.
Special students should not contact individual instructors in the Math Department for course enrollment permissions. Course enrollment for the Math Department is not managed by individual instructors.
Rather, special students should work on filling out an enrollment request form for the semester they'll be enrolling to ask for enrollment permission.
If a special student has already taken math coursework at UW-Madison and therefore explicitly meets the course prerequisites, there is no need to obtain enrollment permission. For instance, if a special student has completed MATH 221 at UW-Madison already, they are eligible to enroll into MATH 222 directly and without any special permissions.
If there are any questions about this, please send an email to Kyle Martinez at placement@math.wisc.edu.