Abstract
We study Humbert's modular equation which characterizes curves of genus two having real multiplication by the quadratic order of discriminant 5. We give it a simple, but general expression as a polynomial in x1;.. .; x6 the coordinate of the Weierstrass points, and show that it is invariant under a transitive permutation group of degree 6 isomorphic to S{fraktur}5. We also prove the rationality of the hypersurface in P5 defined by the generalized modular equation.
Original language | English |
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Pages (from-to) | 171-176 |
Number of pages | 6 |
Journal | Proceedings of the Japan Academy Series A: Mathematical Sciences |
Volume | 85 |
Issue number | 10 |
DOIs | |
Publication status | Published - 2009 Dec |
Externally published | Yes |
Keywords
- Curves of genus two
- Modular equation
- Real multiplication
ASJC Scopus subject areas
- Mathematics(all)