Group actions, divisors, and plane curves
Date of Original Version
After a general discussion of group actions, orbifolds, and weak orbifolds, this note will provide elementary introductions to two basic moduli spaces over the real or complex numbers: first the moduli space of effective divisors with finite stabilizer on the projective space P1, modulo the group of projective transformations of P1; and then the moduli space of curves (or more generally effective algebraic 1-cycles) with finite stabilizer in P2, modulo the group of projective transformations of P2. It also discusses automorphisms of curves and the topological classification of smooth real curves in P2.
Bulletin of the American Mathematical Society
Bonifant, Araceli, and John Milnor. "Group actions, divisors, and plane curves." Bulletin of the American Mathematical Society 57, 2 (2020): 171-267. doi:10.1090/bull/1681.