Reeb stability theorem: Difference between revisions
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== Reeb local stability theorem == |
== Reeb local stability theorem == |
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Theorem<ref name="Reeb">G. Reeb, {{cite book | author=G. Reeb | title=Sur certaines propriétés toplogiques des variétés feuillétées | series=Actualités Sci. Indust. | volume=1183 | publisher=Hermann | location=Paris | year=1952 }}</ref>: ''Let <math>F</math> be a <math>C^1</math>, codimension <math>k</math> [[foliation]] of a [[manifold]] <math>M</math> and <math>L</math> a [[compact space|compact]] leaf with finite [[holonomy|holonomy group]]. There exists a [[Neighbourhood (mathematics)|neighborhood]] <math>U</math> of <math>L</math>, saturated in <math>F</math> (also called invariant), in which all the leaves are compact with finite holonomy groups. Further, we can define a [[Deformation retract#|retraction]] <math>\pi: U\to L</math> such that, for every leaf <math>L'\subset U</math>, <math>\pi|_{L'}:L'\to L</math> is a [[covering]] with a finite number of sheets and, for each <math>y\in L</math>, <math>\pi^{-1}(y)</math> is [[homeomorphism|homeomorphic]] to a [[disk (mathematics)|disk]] of [[dimension]] k and is [[transverse]] to <math>F</math>. The neighborhood <math>U</math> can be taken to be arbitrarily small.'' |
Theorem<ref name="Reeb">G. Reeb, {{cite book | author=G. Reeb | title=Sur certaines propriétés toplogiques des variétés feuillétées | series=Actualités Sci. Indust. | volume=1183 | publisher=Hermann | location=Paris | year=1952 }}</ref>: ''Let <math>F</math> be a <math>C^1</math>, codimension <math>k</math> [[foliation]] of a [[manifold]] <math>M</math> and <math>L</math> a [[compact space|compact]] leaf with finite [[holonomy|holonomy group]]. There exists a [[Neighbourhood (mathematics)|neighborhood]] <math>U</math> of <math>L</math>, saturated in <math>F</math> (also called invariant), in which all the leaves are compact with finite holonomy groups. Further, we can define a [[Deformation retract#|retraction]] <math>\pi: U\to L</math> such that, for every leaf <math>L'\subset U</math>, <math>\pi|_{L'}:L'\to L</math> is a [[covering]] with a finite number of sheets and, for each <math>y\in L</math>, <math>\pi^{-1}(y)</math> is [[homeomorphism|homeomorphic]] to a [[disk (mathematics)|disk]] of [[dimension]] k and is [[Transversality (mathematics)|transverse]] to <math>F</math>. The neighborhood <math>U</math> can be taken to be arbitrarily small.'' |
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The last statement means in particular that, in a neighborhood of the point corresponding to a compact leaf |
The last statement means in particular that, in a neighborhood of the point corresponding to a compact leaf |
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This theorem holds true even when <math>F</math> is a foliation of a [[Manifold#Manifold with boundary|manifold with boundary]], which is, a priori, [[Tangent space|tangent]] |
This theorem holds true even when <math>F</math> is a foliation of a [[Manifold#Manifold with boundary|manifold with boundary]], which is, a priori, [[Tangent space|tangent]] |
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on certain components of the [[Boundary (topology)|boundary]] and [[Transversality|transverse]] on other components.<ref>C. Godbillon, ''Feuilletages, etudies geometriques,'' — Basel, Birkhauser, 1991</ref> In this case it implies [[Reeb sphere theorem]]. |
on certain components of the [[Boundary (topology)|boundary]] and [[Transversality (mathematics)|transverse]] on other components.<ref>C. Godbillon, ''Feuilletages, etudies geometriques,'' — Basel, Birkhauser, 1991</ref> In this case it implies [[Reeb sphere theorem]]. |
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Reeb Global Stability Theorem is false for foliations of codimension greater than one.<ref>W.T.Wu and G.Reeb, ''Sur les éspaces fibres et les variétés feuillitées'', — Hermann, 1952.</ref> However, for some special kinds of foliations one has the following global stability results: |
Reeb Global Stability Theorem is false for foliations of codimension greater than one.<ref>W.T.Wu and G.Reeb, ''Sur les éspaces fibres et les variétés feuillitées'', — Hermann, 1952.</ref> However, for some special kinds of foliations one has the following global stability results: |
Revision as of 05:24, 16 September 2011
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
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 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 leaf.[3][4]
Reeb global stability theorem
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.
- For holomorphic foliations in complex Kähler manifold:
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
- 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
- ^ a b G. Reeb, G. Reeb (1952). Sur certaines propriétés toplogiques des variétés feuillétées. Actualités Sci. Indust. Vol. 1183. Paris: Hermann.
- ^ J. Palis, jr., W. de Melo, Geometric theory of dinamical systems: an introduction, — New-York, Springer,1982.
- ^ T.Inaba, Reeb stability of noncompact leaves of foliations,— Proc. Japan Acad. Ser. A Math. Sci., 59:158{160, 1983 [1]
- ^ 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]
- ^ C. Godbillon, Feuilletages, etudies geometriques, — Basel, Birkhauser, 1991
- ^ W.T.Wu and G.Reeb, Sur les éspaces fibres et les variétés feuillitées, — Hermann, 1952.
- ^ R.A. Blumenthal, Stability theorems for conformal foliations, — Proc. AMS. 91, 1984, p. 55–63. [3]
- ^ J.V. Pereira, Global stability for holomorphic foliations on Kaehler manifolds, — Qual. Theory Dyn. Syst. 2 (2001), 381–384. arXiv:math/0002086v2