Requests to be a TA/grader: Thanks for your interest, but I do not choose the TAs and graders for my classes. If you are a graduate student outside the math department, I believe you should primarily contact your home department for TA/grader assignments. If you are a graduate student within the math department, then I believe your TA/grader assignment is handled by Amy Yung. As far as I know, undergraduate students do not serve as TAs for USC math classes. If you are a USC undergraduate interested in being a grader, I'm not sure how many such positions are available, but you might try contacting Amy Yung, amy(@-symbol)usc.edu, for more information that cannot be found on USC/departmental websites.
Requests to enroll directly in my class: Unfortunately I do not directly handle enrollment in USC classes. You might try contacting Arnold Deal, deal(@-symbol)usc.edu, for enrollment information that cannot otherwise be found on websites such as this one.
Requests from non-USC students to apply to be my graduate student: Thanks for your interest, but I do not directly choose graduate students outside of USC to be enrolled at USC. If you are interested in graduate study at USC, you should first apply for admission into the appropriate program (see e.g. here). (Currently I do not have any role on the graduate admissions committee, so I do not play any role in graduate admissions.) If you are admitted to a USC graduate program I would then be happy to talk further about your graduate studies and research plans.
Requests from PhD students to be a postdoc at USC: Thanks for your interest, but I am not currently on the postdoctoral selection committee, so I do not play any role in the selection of postdocs. If you are pursuing a postdoc at USC, I would encourage you to first apply to the relevant position when it appears on the mathjobs website. If you are offered a position at USC, I would then be happy to talk further about your research plans.
Requests for supervising undergraduate research: Thanks for your interest, but due to existing commitments, I do not currently have time for supervising undergraduates at USC. I am happy to offer some advice, direction, or even sporadic supervision for USC undergraduates, though two people in the math department to consider contacting for more substantial supervision include: David Crombecque, crombecq(@-symbol)email.usc.edu, and Neelesh Tiruviluamala, tiruvilu(@-symbole)usc.edu. (See also here.) USC has some good research program links here, here and here. There are a lot of good summer research opportunities such as Math REUs (mostly for US citizens) and IPAM RIPS.
Requests for supervising high school students, high school tutoring, etc.: Thanks for your interest, but due to existing commitments, I do not currently have time for such activities. USC has summer programs for high school students. There are also various math circles in the LA area such as the UCLA Olga Radko Endowed Math Circle and the Venice Math Circle. For tutoring, USC has a webpage with information. Also, the UCLA math department maintains a list of graduate student tutors.