Invariants of a genus 2 curve (reviewed)

Invariants of a genus 2 curve include:

• the discriminant $\Delta$,
• the conductor $N$ of its Jacobian,
• its geometric invariants, which may be expressed as Igusa-Clebsch invariants $I_2,I_4,I_6,I_{10}$, Igusa invariants $J_2,J_4,J_6,J_8,J_{10}$, or G2-invariants $g_1,g_2,g_3$.