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MiS Preprint
64/2008

Theta functions on the Kodaira-Thurston manifold

William Kirwin and Alejandro Uribe

Abstract

The Kodaira--Thurston manifold $M$ is a compact, 4-dimensional nilmanifold which is symplectic and complex but not Kaehler. We describe a construction of theta-functions associated to $M$ which parallels the classical theory of theta-functions associated to the torus (from the point of view of representation theory and geometry), and yields pseudoperiodic complex-valued functions on $R^4$.

There exists a three-step nilpotent Lie group $G$ which acts transitively on the Kodaira-Thurston manifold, and on the universal cover of $M$ in a Hamiltonian fashion. The theta-functions discussed in this paper are intimately related to the representation theory of $G$ in much the same way that the classical theta-functions are related to the Heisenberg group. One aspect of our results is a connection between the representation theory of $G$ and the existence of Lagrangian and special Lagrangian foliations and torus fibrations in $M$; in particular, we show that $G$-invariant special Lagrangian foliations can be detected by a simple algebraic condition on certain subalgebras of the Lie algebra of $G$.

Crucial to our generalization of theta-functions is the spectrum of the Laplacian acting on sections of certain line bundles over $M$. One corollary of our work is a verification of a theorem of Guillemin-Uribe describing the structure (in the semiclassical limit) of the low-lying spectrum of this Laplacian.

Received:
26.09.08
Published:
30.09.08
MSC Codes:
53D, 11F27, 43A

Related publications

inJournal
2010 Repository Open Access
William D. Kirwin and Alejandro Uribe

Theta functions on the Kodaira-Thurston manifold

In: Transactions of the American Mathematical Society, 362 (2010) 2, pp. 897-932