Manifolds and Modular FormsDuring the winter term 1987/88 I gave a course at the University of Bonn under the title "Manifolds and Modular Forms". Iwanted to develop the theory of "Elliptic Genera" and to leam it myself on this occasion. This theory due to Ochanine, Landweber, Stong and others was relatively new at the time. The word "genus" is meant in the sense of my book "Neue Topologische Methoden in der Algebraischen Geometrie" published in 1956: A genus is a homomorphism of the Thom cobordism ring of oriented compact manifolds into the complex numbers. Fundamental examples are the signature and the A-genus. The A-genus equals the arithmetic genus of an algebraic manifold, provided the first Chem class of the manifold vanishes. According to Atiyah and Singer it is the index of the Dirac operator on a compact Riemannian manifold with spin structure. The elliptic genera depend on a parameter. For special values of the parameter one obtains the signature and the A-genus. Indeed, the universal elliptic genus can be regarded as a modular form with respect to the subgroup r (2) of the modular group; the two cusps o giving the signature and the A-genus. Witten and other physicists have given motivations for the elliptic genus by theoretical physics using the free loop space of a manifold. |
Contents
Chapter | 1 |
Chapter | 5 |
Representations and vector bundles | 9 |
Copyright | |
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Â-genus Appendix c₁ Chern class cobordism coefficients cohomology compact complex manifold component cusps defined denote differentiable manifold differential equation dimension Dirac operator divisor E₁ elliptic complex elliptic curve elliptic function elliptic genera elliptic genus elliptic with respect equivariant Euler number fibre bundles finite fixed point form of weight Fourier expansion Hence Hirzebruch holomorphic homogeneous index theorem integral invariant isomorphism L-genus lattice Lemma line bundle meromorphic function modular form modulo multiplicative N-division point normalization obtain oriented p-function P₁ P₁(C poles Pontrjagin classes Pontrjagin numbers power series Q(x projective spaces Proof q-expansion Remark representation resp S¹ acts S¹-action sequence sign q signature subgroup submanifold T₁(N tangent bundle theta function topological trivial values vanish vector bundle w₁ w₂ Witten Xy(q yields zero Zolotarev polynomials ΣΣ