// Workers AI · dad joke modeWhy was the Humbert surface sad? It was feeling down.

In algebraic geometry, a Humbert surface, studied by Humbert (1899), is a surface in the moduli space of principally polarized abelian surfaces consisting of the surfaces with a symmetric endomorphism of some fixed discriminant.

References

• Hulek, Klaus; Kahn, Constantin; Weintraub, Steven H. (1993), Moduli spaces of abelian surfaces: compactification, degenerations, and theta functions, de Gruyter Expositions in Mathematics, vol. 12, Berlin: Walter de Gruyter & Co., ISBN 978-3-11-013851-1, MR 1257185
• Humbert, G., Sur les fonctionnes abéliennes singulières. I, II, III. J. Math. Pures Appl. serie 5, t. V, 233–350 (1899); t. VI, 279–386 (1900); t. VII, 97–123 (1901)