Reeb stability theorem

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.

foliation of a manifold

a compact leaf with finite holonomy group.

(also called invariant), in which all the leaves are compact with finite holonomy groups.

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 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

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

[3][4] 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.

, codimension one foliation of a closed manifold

with finite fundamental group, then all the leaves of

are compact, with finite fundamental group.

is transversely orientable, then every leaf of

is the total space of a fibration

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: Theorem:[7] Let

be a complete conformal foliation of codimension

has a compact leaf with finite holonomy group, then all the leaves of

are compact with finite holonomy group.

be a holomorphic foliation of codimension

in a compact complex Kähler manifold.

has a compact leaf with finite holonomy group then every leaf of

is compact with finite holonomy group.