Riemann form
Appearance
In
modular forms
, is the following data:
- A lattice Λ in a complex vector space Cg.
- An alternating bilinear form α from Λ to the integers satisfying the following Riemann bilinear relations:
- the real linear extension αR:Cg × Cg→R of α satisfies αR(iv, iw)=αR(v, w) for all (v, w) in Cg × Cg;
- the associated positive-definite.
(The hermitian form written here is linear in the first variable.)
Riemann forms are important because of the following:
- The factor of automorphyis a Riemann form.
- Conversely, given any Riemann form, we can construct a factor of automorphy such that the alternatization of its Chern class is the given Riemann form.
Furthermore, the complex torus Cg/Λ admits the structure of an abelian variety if and only if there exists an alternating bilinear form α such that (Λ,α) is a Riemann form.
References
- Milne, James (1998), Abelian Varieties, retrieved 2008-01-15
- Hindry, Marc; Silverman, Joseph H. (2000), Diophantine Geometry, An Introduction, Graduate Texts in Mathematics, vol. 201, New York, )
- MR 0282985
- "Abelian function", Encyclopedia of Mathematics, EMS Press, 2001 [1994]
- "Theta-function", Encyclopedia of Mathematics, EMS Press, 2001 [1994]