Let be an -Manifold and let denote a Partition of into Disjoint path-connected Subsets. Then is called a foliation of of codimension (with ) if there Exists a Cover of by Open Sets , each equipped with a Homeomorphism or which throws each nonempty component of onto a parallel translation of the standard Hyperplane in . Each is then called a Leaf and is not necessarily closed or compact.
See also Leaf (Foliation), Reeb Foliation
Rolfsen, D. Knots and Links. Wilmington, DE: Publish or Perish Press, p. 284, 1976.