Date and time: Wed, 02/06/2019 - 2:00pm Room 304, Boyd Graduate Studies Bldg. Seminars Speaker: D. Zureick-Brown, Georgia Tech Title: The canonical ring of a stacky curve Abstract: We give a generalization to stacks of the classical (1920's) theorem of Petri -- we give a presentation for the canonical ring of a stacky curve. This is motivated by the following application: we give an explicit presentation for the ring of modular forms for a Fuchsian group with cofinite area, which depends on the signature of the group. This is joint work with John Voight.