Paper 2, Section II, H

Algebraic Geometry
Part II, 2016

In this question we work over an algebraically closed field of characteristic zero. Let Xo=Z(x6+xy5+y61)A2X^{o}=Z\left(x^{6}+x y^{5}+y^{6}-1\right) \subset \mathbb{A}^{2} and let XP2X \subset \mathbb{P}^{2} be the closure of XoX^{o} in P2.\mathbb{P}^{2} .

(a) Show that XX is a non-singular curve.

(b) Show that ω=dx/(5xy4+6y5)\omega=d x /\left(5 x y^{4}+6 y^{5}\right) is a regular differential on XX.

(c) Compute the divisor of ω\omega. What is the genus of XX ?