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We give an $h$--principle type result for a class of Legendrian embeddings in contact manifolds of dimension at least $5$. These Legendrians, referred to as loose, have trivial pseudo-holomorphic invariants. We demonstrate they are…

Symplectic Geometry · Mathematics 2019-03-13 Emmy Murphy

We present the first examples of elements in the fundamental group of the space of Legendrian links in the standard contact 3-sphere whose action on the Legendrian contact DGA is of infinite order. This allows us to construct the first…

Symplectic Geometry · Mathematics 2022-08-04 Roger Casals , Lenhard Ng

We will work with codimension one holomorphic foliations over the complex projective space, represented by integrable forms $\omega\in H^0(\Omega^1_{\PP^n}(e))$. Our main result is that, under suitable hypotheses, the Kupka set of the…

Algebraic Geometry · Mathematics 2020-07-20 Omegar Calvo-Andrade , Ariel Molinuevo , Federico Quallbrunn

A foliation is said to admit a foliated contact structure if there is a codimension 1 distribution in the tangent space of the foliation such that the restriction to any leaf is contact. We prove a version of the Weinstein conjecture in the…

Symplectic Geometry · Mathematics 2015-09-18 Álvaro del Pino , Francisco Presas

In this note, we define a new invariant of a Legendrian knot in a contact manifold using an open book decomposition supporting the contact structure. We define the support genus sg(L) of a Legendrian knot L in a contact 3-manifold (M, \xi)…

Geometric Topology · Mathematics 2009-11-14 Sinem Celik Onaran

We show that for a big class of contact manifolds the groups of order $\leq n$ invariants (with values in an arbitrary Abelian group) of Legendrian, of transverse and of framed knots are canonically isomorphic. On the other hand for an…

Symplectic Geometry · Mathematics 2007-05-23 Vladimir Tchernov

Let $\mathcal{F}$ be a singular holomorphic foliation of dimension $k>1$ on a projective $n$-manifold $X$. Assume that the determinant of the normal sheaf of $\mathcal{F}$ is ample (as is always the case when $X=\mathbb{P}^{n}$), and that…

Algebraic Geometry · Mathematics 2026-03-16 Omegar Calvo-Andrade , Maurício Corrêa , Marcos Jardim , José Seade

We explain a connection between the algebraic and geometric properties of groups of contact transformations, open book decompositions, and flexible Legendrian embeddings. The main result is that, if a closed contact manifold $(V, \xi)$ has…

Symplectic Geometry · Mathematics 2019-02-01 Sylvain Courte , Patrick Massot

We establish a full $h-$principle ($C^0-$close, relative, parametric) for the simplification of singularities of Lagrangian and Legendrian fronts. More precisely, we prove that if there is no homotopy theoretic obstruction to simplifying…

Symplectic Geometry · Mathematics 2017-04-07 Daniel Alvarez-Gavela

We construct infinite families of non-simple isotopy classes of links in overtwisted contact structures on $S^1$-bundles over surfaces. These examples include: (1) a pair of Legendrian links that are not Legendrian isotopic, but which are…

Geometric Topology · Mathematics 2026-01-21 Patricia Cahn , Rima Chatterjee , Vladimir Chernov

We investigate families of Legendrian submanifolds of 1-jet spaces by developing and applying a theory of families of generating family homologies. This theory allows us to detect an infinite family of loops of Legendrian n-spheres embedded…

Symplectic Geometry · Mathematics 2013-11-05 Joshua M. Sabloff , Michael G. Sullivan

We consider a class of singular foliations in the sense of Androulidakis and Skandalis that we call transverse order $k$ foliations. These have a finite number of leaves: one hypersurface (the singular leaf) together with the components of…

Operator Algebras · Mathematics 2024-02-09 Michael Francis

In this article we introduce and analyze in detail singular contact structures, with an emphasis on $b^m$-contact structures, which are tangent to a given smooth hypersurface $Z$ and satisfy certain transversality conditions. These singular…

Symplectic Geometry · Mathematics 2025-09-01 Eva Miranda , Cédric Oms

Given a singular foliation, we attach an "essential isotropy" group to each of its leaves, and show that its discreteness is the integrability obstruction of a natural Lie algebroid over the leaf. We show that a condition ensuring…

Differential Geometry · Mathematics 2013-11-18 Iakovos Androulidakis , Marco Zambon

We define a differential graded algebra associated to Legendrian knots in Seifert fibered spaces with transverse contact structures. This construction is distinguished from other combinatorial realizations of contact homology invariants by…

Symplectic Geometry · Mathematics 2010-12-14 Joan E. Licata , Joshua M. Sabloff

Given a null-cobordant oriented framed link $L$ in a closed oriented $3$--manifold $M$, we determine those links in $M \setminus L$ which can be realized as the singular point set of a generic map $M \to \mathbb{R}^2$ that has $L$ as an…

Geometric Topology · Mathematics 2018-04-03 Osamu Saeki

We associate a Lie $\infty$-algebroid to every resolution of a singular foliation, where we consider a singular foliation as a locally generated $\mathscr{O}$-submodule of vector fields on the underlying manifold closed under Lie bracket.…

Differential Geometry · Mathematics 2021-01-05 Camille Laurent-Gengoux , Sylvain Lavau , Thomas Strobl

Let $M$ be a surface with a Riemannian metric and $UM$ the unit tangent bundle over $M$ with the canonical contact sub-Riemannian structure $D$ on $UM$. In this paper, the complete local classification of singularities, under the Legendre…

Differential Geometry · Mathematics 2022-12-16 Goo Ishikawa , Yumiko Kitagawa

In this article, for holomorphic foliations of codimension one at $(\mathbb{C}^{3},0)$, we define the family of second type foliations. This is formed by foliations having, in the reduction process by blow-up maps, only well oriented…

Dynamical Systems · Mathematics 2017-08-03 Gilberto Cuzzuol , Rogério Mol

We identify the canonical contact structure on the link of a simple elliptic or cusp singularity by drawing a Legendrian handlebody diagram of one of its Stein fillings. We also show that the canonical contact structure on the link of a…

Geometric Topology · Mathematics 2014-12-25 Mohan Bhupal , Burak Ozbagci