Uploaded March 2021 | Updated September 2026, 1 week ago

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This lecture is part of an online graduate course on modular forms.

We describe the fundamental domain of SL2(Z) acting on the upper half plane.

For the other lectures in the course see youtube.com/playlist?list=PL8yHsr3EFj51HisRtNyzHX-Xyg6I3Wl2F