Modular Functions and Modular Forms by James S. Milne
ID: modular-functions-and-modular-forms-by-james-s-milne
Primary text: www.jmilne.org/math/CourseNotes/MF.pdf
Section 2 develops modular curves; Section 4 defines modular functions and modular forms and their lattice interpretation; Section 9 relates cusp forms to Dirichlet series and functional equations.
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