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Reeb stability theorem

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In mathematics, Reeb stability theorem, named after Georges Reeb, asserts that if one leaf of a codimension-one foliation is closed and has finite fundamental group, then all the leaves are closed and have finite fundamental group.

Reeb local stability theorem

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Theorem:[1] Let be a , codimension foliation of a manifold and a compact leaf with finite holonomy group. There exists a neighborhood of , saturated in (also called invariant), in which all the leaves are compact with finite holonomy groups. Further, we can define a retraction such that, for every leaf , is a covering map with a finite number of sheets and, for each , is homeomorphic to a disk of dimension k and is transverse to . The neighborhood can be taken to be arbitrarily small.

The last statement means in particular that, in a neighborhood of the point corresponding to a compact leaf with finite holonomy, the space of leaves is Hausdorff. Under certain conditions the Reeb local stability theorem may replace the Poincaré–Bendixson theorem in higher dimensions.[2] This is the case of codimension one, singular foliations , with , and some center-type singularity in .

The Reeb local stability theorem also has a version for a noncompact codimension-1 leaf.[3][4]

Reeb global stability theorem

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An important problem in foliation theory is the study of the influence exerted by a compact leaf upon the global structure of a foliation. For certain classes of foliations, this influence is considerable.

Theorem:[1] Let be a , codimension one foliation of a closed manifold . If contains a compact leaf with finite fundamental group, then all the leaves of are compact, with finite fundamental group. If is transversely orientable, then every leaf of is diffeomorphic to ; is the total space of a fibration over , with fibre , and is the fibre foliation, .

This theorem holds true even when is a foliation of a manifold with boundary, which is, a priori, tangent on certain components of the boundary and transverse on other components.[5] In this case it implies Reeb sphere theorem.

Reeb Global Stability Theorem is false for foliations of codimension greater than one.[6] However, for some special kinds of foliations one has the following global stability results:

  • In the presence of a certain transverse geometric structure:

Theorem:[7] Let be a complete conformal foliation of codimension of a connected manifold . If has a compact leaf with finite holonomy group, then all the leaves of are compact with finite holonomy group.

Theorem:[8] Let be a holomorphic foliation of codimension in a compact complex Kähler manifold. If has a compact leaf with finite holonomy group then every leaf of is compact with finite holonomy group.

References

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  • C. Camacho, A. Lins Neto: Geometric theory of foliations, Boston, Birkhauser, 1985
  • I. Tamura, Topology of foliations: an introduction, Transl. of Math. Monographs, AMS, v.97, 2006, 193 p.

Notes

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  1. ^ a b G. Reeb (1952). Sur certaines propriétés toplogiques des variétés feuillétées. Actualités Sci. Indust. Vol. 1183. Paris: Hermann.
  2. ^ J. Palis, jr., W. de Melo, Geometric theory of dynamical systems: an introduction, — New-York, Springer,1982.
  3. ^ T.Inaba, Reeb stability of noncompact leaves of foliations,— Proc. Japan Acad. Ser. A Math. Sci., 59:158{160, 1983 [1]
  4. ^ J. Cantwell and L. Conlon, Reeb stability for noncompact leaves in foliated 3-manifolds, — Proc. Amer.Math.Soc. 33 (1981), no. 2, 408–410.[2]
  5. ^ C. Godbillon, Feuilletages, etudies geometriques, — Basel, Birkhauser, 1991
  6. ^ W.T.Wu and G.Reeb, Sur les éspaces fibres et les variétés feuillitées, — Hermann, 1952.
  7. ^ R.A. Blumenthal, Stability theorems for conformal foliations, — Proc. AMS. 91, 1984, p. 55–63. [3]
  8. ^ J.V. Pereira, Global stability for holomorphic foliations on Kaehler manifolds, — Qual. Theory Dyn. Syst. 2 (2001), 381–384. arXiv:math/0002086v2