I'm looking for a major in Theoretical Computer Science; specifically, I'm interested on complexity theory and probabilistic automata theory. As I'm graduating in one year, what advanced courses in math (like Galois theory or Harmonic analysis, for example) do you think would be useful to take over the next two semesters? Why?
(A summary of the comments to the questions)
pretty much any area of mathematics could be important in TCS, so you should do the best to strengthen your math background. Any tool you learn is a gain, and may be employed in some TCS (sub-)field.
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