Non-esistenza di cusps nella geometria asintotica delle foglie
Let Θ denote the class of essential tori in a closed braid complement which admit a standard tiling in the sense of Birman and Menasco [Birman J.S., Menasco W.W., Special positions for essential tori in link complements, Topology, 1994, 33(3), 525–556]. Moreover, let R denote the class of thin tiled tori in the sense of Ng [Ng K.Y., Essential tori in link complements, J. Knot Theory Ramifications, 1998, 7(2), 205–216]. We define the subclass B ⊂ Θ of typical tiled tori and show that R ⊂ B. We also...
We give several sufficients conditions for a 2-cycle of Diff (resp. Diff) represented by a foliated -(resp. -) bundle over a 2-torus to be homologous to zero. Such a 2-cycle is determined by two commuting diffeomorphisms , of (resp. ). If , have fixed points, we construct decompositions: , , where the interiors of Supp Supp are disjoint, and and belong either to ( Diff) or to a one-parameter subgroup generated by a -vectorfield . Under some conditions on the norms...
We consider the problem of extending the result of J.-P. Jouanolou on the density of singular holomorphic foliations on without algebraic solutions to the case of foliations by curves on . We give an example of a foliation on with no invariant algebraic set (curve or surface) and prove that a dense set of foliations admits no invariant algebraic set.
Given a non-singular holomorphic foliation on a compact manifold we analyze the relationship between the versal spaces and of deformations of as a holomorphic foliation and as a transversely holomorphic foliation respectively. With this purpose, we prove the existence of a versal unfolding of parametrized by an analytic space isomorphic to where is smooth and : is the forgetful map. The map is shown to be an epimorphism in two situations: (i) if , where is the sheaf of...
The class of locally connected and locally homeomorphically homogeneous topological spaces such that every one-to-one continuous mapping of an open subspace into the space is open has been considered. For a foliation F [3] on a Sikorski differential space M with leaves having the above properties it is proved that for some open sets U in M covering the set of all points of M the connected components of U ∩ L̲ in the topology of M coincide with the connected components in the topology of L for L∈...
Riemannian foliations constitute an important type of foliated structures. In this note we prove two theorems connecting the algebraic structure of Lie algebras of foliated vector fields with the smooth structure of a Riemannian foliation.
For a Riemannian foliation, the topology of the corresponding spectral sequence is used to characterize the existence of a bundle-like metric such that the leaves are minimal submanifolds. When the codimension is , a simple characterization of this geometrical property is proved.
Two significant directions in the development of jet calculus are showed. First, jets are generalized to so-called quasijets. Second, jets of foliated and multifoliated manifold morphisms are presented. Although the paper has mainly a survey character, it also includes new results: jets modulo multifoliations are introduced and their relation to (R,S,Q)-jets is demonstrated.