In mathematics, a solvmanifold is a homogeneous space of a connected solvable Lie group. It may also be characterized as a quotient of a connected solvable Lie group by a closed subgroup. (Some authors also require that the Lie group be simply-connected, or that the quotient be compact.) A special class of solvmanifolds, nilmanifolds, was introduced by Anatoly Maltsev, who proved the first structural theorems. Properties of general solvmanifolds are similar, but somewhat more complicated.
Examples
- A solvable Lie group is trivially a solvmanifold.
- Every nilpotent group is solvable, therefore, every nilmanifold is a solvmanifold. This class of examples includes n-dimensional tori and the quotient of the 3-dimensional real Heisenberg group by its integral Heisenberg subgroup.
- The Möbius band and the Klein bottle are solvmanifolds that are not nilmanifolds.
- The mapping torus of an Anosov diffeomorphism of the n-torus is a solvmanifold. For , these manifolds belong to Sol, one of the eight Thurston geometries.
Properties
- A solvmanifold is diffeomorphic to the total space of a vector bundle over some compact solvmanifold. This statement was conjectured by George Mostow and proved by Louis Auslander and Richard Tolimieri.
- The fundamental group of an arbitrary solvmanifold is polycyclic.
- A compact solvmanifold is determined up to diffeomorphism by its fundamental group.
- Fundamental groups of compact solvmanifolds may be characterized as group extensions of free abelian groups of finite rank by finitely generated torsion-free nilpotent groups.
- Every solvmanifold is aspherical. Among all compact homogeneous spaces, solvmanifolds may be characterized by the properties of being aspherical and having a solvable fundamental group.
Completeness
Let be a real Lie algebra. It is called a complete Lie algebra if each map
in its adjoint representation is hyperbolic, i.e., it has only real eigenvalues. Let G be a solvable Lie group whose Lie algebra is complete. Then for any closed subgroup of G, the solvmanifold is a complete solvmanifold.
References
- Auslander, Louis (1973), "An exposition of the structure of solvmanifolds. Part I: Algebraic theory" (PDF), Bulletin of the American Mathematical Society, 79 (2): 227–261, doi:10.1090/S0002-9904-1973-13134-9, MR 0486307
- — (1973), "Part II: $G$-induced flows", Bull. Amer. Math. Soc., 79 (2): 262–285, doi:10.1090/S0002-9904-1973-13139-8, MR 0486308
- Cooper, Daryl; Scharlemann, Martin (1999), "The structure of a solvmanifold's Heegaard splittings" (PDF), Proceedings of 6th Gökova Geometry-Topology Conference, Turkish Journal of Mathematics, 23 (1): 1–18, ISSN 1300-0098, MR 1701636
- Gorbatsevich, V. V. (2001) [1994], "Solv manifold", Encyclopedia of Mathematics, EMS Press