Questions tagged [contact-geometry]

Contact manifolds, contact structures, contact forms, Reeb dynamics, Legendrian knots, contact homology, symplectic field theory

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Legendrian surgery and invertible elements in zeroth degree symplectic cohomology

Is there anything known about the relation between Legendrian handle attachment and invertible elements in $\mathit{SH}^0(M)$? As the simplest interesting case, take $M_0$ to be the cotangent bundle $...
YHBKJ's user avatar
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Stabilizing an open book with Anosov piece

It was proven by Colin and Honda in Stabilizing the monodromy of an open book decomposition that any diffeomorphism can be made pseudo-Anosov and right-veering after a series of positive ...
Paul's user avatar
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Contact 3-manifolds with hyperkahler Stein fillings?

Is there any classification result on (homeomorphism type) of contact 3-manifolds $\Sigma$ that have Stein filling $W$ that is 1. Hyperkahler (s.t. Stein structure is the Kahler part of it) 2. not ...
Filip's user avatar
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Evolute hypersurfaces

Do you have any references on studies examining the evolute (or focal) hypersurface to a given hypersurface in dimension greater than 3 ? The evolute can for instance be defined as the envelope of ...
Clement's user avatar
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15 votes
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Examples of odd-dimensional manifolds that do not admit contact structure

I'm having an hard time trying to figuring out a concrete example of an odd-dimensional closed manifold that do not admit any contact structure. Can someone provide me with some examples?
Overflowian's user avatar
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Symplectic vector fields everywhere transverse to a co-dimension one hypersurface

Usually when speaking about vector fields transverse to a hypersurface in a symplectic manifold, we talk about Liouville vector fields, i.e. vector fields $X$ with the property that $\mathcal{L}_X\...
R Mary's user avatar
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First Chern Class of Contact Structure which is not Torsion

Let $(M,\xi)$ be a closed connected $3-$dimensional contact manifold with contact structure $\xi$. It is known that the first Chern class $c_{1}(\xi)$ defines an element in $H^{2}(M;\mathbb{Z})$ and ...
Raffael's user avatar
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Is there any known relationship between sutured contact homology and Legendrian contact homology?

On one hand, Colin-Ghiggini-Honda-Hutchings' construction (https://arxiv.org/abs/1004.2942) provides an invariant of a Legendrian $L$ in a closed contact manifold $(M,\xi)$ via the sutured contact ...
Ian Montague's user avatar
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On different definitions of a prequantization space

Geometric quantization associates to a symplectic manifold $(M,\omega)$ a hermitian line bundle $L \to M$ with connection $\nabla$ whose curvature is $\omega$ (up to some constant). Without talking ...
BrianT's user avatar
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On the existence and classification of prequantization spaces over a closed symplectic manifold

Let $(M,\omega)$ be a closed symplectic manifold. If the cohomology class $[\omega]$ is rational, that is if it lies in the image of the natural homomorphism $H^2(M,\mathbb{Z}) \to H^2(M,\mathbb{R})$, ...
BrianT's user avatar
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The Lefschetz operator

Let $\omega=\sum_{i=1}^n dx_i\wedge dy_i\in\bigwedge^2(\mathbb{R}^{2n})^*$ be a standard symplectic form. The following result is due to Lefschetz: For $k\leq n$, the Lefschetz operator $L^{n-k}:\...
Piotr Hajlasz's user avatar
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Bound on critical points of Lefschetz fibration over the disk with prescribed monodromy

Let $\phi$ be a right-veering diffeomorphism of a surface $\Sigma$ of genus $g$ and $r$ boundary components. Suppose that the diffeomorphism is freely periodic so if $M$ is the associated open book ...
Paul's user avatar
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16 votes
1 answer
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Weinstein neighborhood theorem for Lagrangians with Legendrian boundary

$\require{AMScd}$ Weinstein's neighborhood theorem says that every Lagrangian has a standard neighborhood. The more precise statement goes like this. Theorem 1: (Lagrangian Neighborhood Theorem) Let $...
Julian Chaidez's user avatar
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Contact geometry: approximation of Legendrian mappings

Let $\alpha$ be a standard contact form on $\mathbb{R}^{2n+1}$. We say that a map $f:\mathbb{R}^k\to\mathbb{R}^{2n+1}$ contact if $f^*\alpha=0$. Question 1. Is it true that a $C^1$-contact ...
Piotr Hajlasz's user avatar
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1 answer
592 views

Physical intuition behind prequantization spaces

Given a symplectic manifold $(M,\omega)$ with integral symplectic form, that is $$\omega \in \text{Im}(H_2(M,\mathbb{Z}) \to H_2(M,\mathbb{R})),$$ one can form a so-called prequantization space, that ...
BrianT's user avatar
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Where can I find good surveys on Symplectic and Contact geometry

Are there any good survey articles in symplectic and contact geometry, which focus on the "big picture", i.e how this discipline fits into the mathematical world ? In the symplectic case : I am ...
BrianT's user avatar
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21 votes
3 answers
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Proof of Giroux's correspondence

It is extensively used and cited the following statement due to Giroux: Given a closed $3$-manifold $M$, there is a $1:1$ correspondence between oriented contact structures on $M$ up to isotopy and ...
Paul's user avatar
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10 votes
2 answers
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Is the Lisca-Matic bound (aka slice-Bennequin bound) strictly stronger than the Bennequin bound?

The Bennequin bound [1] says that, for a transverse knot (or later link) $K$ in $S^3$, $$\mathrm{sl}(K) \le - \chi(\Sigma)$$ for any Seifert surface $\Sigma$ for $K$, where $\mathrm{sl}$ is the self-...
Dylan Thurston's user avatar
4 votes
2 answers
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Non-trivial examples of overtwisted contact structures

Are there any non-trivial examples of overtwisted contact structures on closed contact $3$-manifolds? By non-trivial I mean any examples besides the trivial one $\xi = \ker (\cos(r)dz - r \sin(r)d\...
Mortel's user avatar
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Is there a simply connected contact manifold, "non-exactly" fillable, cappable, such that the whole thing is symplectically aspherical?

Is there an example of a simply connected contact manifold W, with a non exact symplectic filling $M_1$, (that is, $M_1$ is a symplectic manifold, with contact boundary $W$ and a Liouville vector ...
Yaniv Ganor's user avatar
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7 votes
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Correct notion of chain homotopy for linearized homology of augmented DGAs?

$\require{AMScd}$ Preliminaries: Let $(A,\partial)$ be a differential graded $k$-algebra with an augmentation $\epsilon$. That is, $\epsilon$ is a DGA map $\epsilon:(A,\partial) \to k$ where $k$ is ...
Julian Chaidez's user avatar
3 votes
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217 views

Lutz twist and open book decompositions

Let $M^3$ be a closed oriented 3-manifold, endowed with an open book decomposition. Consider a section of the open book, that is a knot $K \subset M$ disjoint from the binding and meeting every page ...
Daniele Zuddas's user avatar
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Right-veering periodic automorphisms of surfaces that are not composition of right-handed Dehn twists

Basically the title of the question. For the sake of completeness I state an introduction to the question. In "Right-veering diffeomorphisms of compact surfaces with boundary I" and II, the authors ...
Paul's user avatar
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Ozsváth-Szabó's contact invariant on the Brieskorn sphere $\Sigma(2,3,6m+1)$

According to Theorem 1.7 of Mark-Tosun's paper, the Brieskorn sphere $\Sigma(2,3,6m+1)$ admits two tight contact structure $\xi_{i}\ (i=0,1)$. They are both Stein fillable and they are contactomorphic ...
user44651's user avatar
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12 votes
3 answers
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Do contact and CR structures have corresponding $G$-structures?

For an $n$-dimensional manifold $M$, almost complex and almost symplectic structures on $M$ correspond to reductions on the structure group of the tangent bundle, introducing a $\operatorname{GL}(n/2,\...
E. Addison's user avatar
12 votes
2 answers
746 views

Solving ODE via contact geometry

I have been reading H. Geiges' "A Brief History of Contact Geometry and Topology". According to him contact transformations were introduced as a geometric tool to study systems of differential ...
Lukas S's user avatar
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An equivalent definition for contact pair manifolds

َContact manifold A $(2n + 1)$-dimensional manifold $M$ is said to be a contact manifold if it admits a global 1-form $\eta$ such that $\eta\wedge (d\eta)^n\neq 0$. There is an equivalent ...
C.F.G's user avatar
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The isotopy class of a Boothby-Wang contact structure

Let $p:\Sigma\to M$ be a non-trivial principal $S^1$-bundle over a closed orientable surface $M$. Let's call $V$ the vector field generating the $S^1$-action. It is known that there exists a Boothby-...
GabrieleBenedetti's user avatar
7 votes
1 answer
544 views

"Explicit" perturbations of Morse-Bott functions

There are explicit perturbations of Morse-Bott functions $f:X\to\mathbb{R}$ used in the literature (ex: Austin-Braam, Banyaga-Hurtubise, Bourgeois) to help solve various problems (ex: building Morse ...
Chris Gerig's user avatar
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5 votes
1 answer
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Almost complex structures on a 4-ball that are not tamed

Recall that an almost complex structure $J$ on a manifold $M^{2n}$ is called tamed if there exists a symplectic form $\omega$ on $M^{2n}$ such that $\omega(v,Jv)>0$ for any non-zero tangent vector $...
aglearner's user avatar
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1 vote
0 answers
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Confusion about the definition of a formal Legendrian isotopy

We say two Legendrian embeddings $f_0,f_1:L^n\rightarrow (Y^{2n+1},\xi)$ are formally isotopic if there is a smooth isotopy $f_t$ connecting $f_0$ and $f_1$ and a bundle monomorphism $F_t^s:TL\...
milou123's user avatar
6 votes
1 answer
393 views

Non-Reeb vector fields on the three-sphere

Let $X$ be the Hopf vector field on the three-sphere. Is there a smooth nowhere zero function $f$ so that the modified vector field $fX$ is not the Reeb vector field of any contact form on the three-...
alvarezpaiva's user avatar
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9 votes
1 answer
614 views

Reeb flows on $S^3$ versus volume preserving flows

Is there an example of a smooth vector field $v$ on $S^3$ such that $v$ preserves a volume form and $v$ is not a Reeb vector field? Recall that $v$ is a Reeb vector field if there exists a contact $...
aglearner's user avatar
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3 votes
1 answer
475 views

When is the gradient of a Hamiltonian function a Liouville vector field?

Let $(M, \omega)$ be a symplectic manifold, $H$ a Hamiltonian function on $M$, $Y = H^{-1}(c)$ for a regular value $c$, and $J$ a compatible almost complex structure. If $X_H$ is the Hamiltonian ...
dorebell's user avatar
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7 votes
0 answers
205 views

When do geodesics reconverge?

Say I stand at the north pole and talk; in sufficiently frictionless conditions, one imagines that someone standing at the south pole could listen. More generally, say $M$ is a compact Riemannian ...
Vivek Shende's user avatar
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3 votes
1 answer
269 views

Degenerate Reeb orbits

I am reading about contact homology and ECH, and realized that I do not see what goes wrong with the definition of these theories, if one takes into count degenerate Reeb orbits. In general, I would ...
Alex Batisto's user avatar
1 vote
1 answer
315 views

Conformal Killing vector field on contact manifolds

An interesting class of contact manifolds is the class of $K$-contact manifolds ($\mathcal{L}_\xi g=0$) which have been studied by many authors. It is natural to study conformal Killing-contact ...
C.F.G's user avatar
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4 votes
0 answers
79 views

Neighborhood of (singular) Legendrian with convex boundary

Let $(M, \xi)$ be a contact manifold, and $\Lambda \subset M$ a closed connected Legendrian with a tubular open neighborhood $W$. The question is that, can one find a smaller tubular neighborhood $U \...
Peng's user avatar
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17 votes
1 answer
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What is the mirror of symplectic field theory?

Mirror symmetry is, very roughly, a relation between symplectic geometry on one side and complex/algebraic geometry on the other side. For example, counts of pseudoholomorphic spheres in a closed ...
user25309's user avatar
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0 votes
1 answer
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On generalized Tanaka connection

Many authors used the Tanaka connection in their papers such as [1] to define new Tanaka connection so-called Generalized Tanaka connection $^*\nabla$ on a contact Riemannian manifold $(M,\eta,\xi,\...
C.F.G's user avatar
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4 votes
0 answers
236 views

Contact manifolds and pseudodifferential operators

By way of background, I am currently trying to understand the theory of pseudodifferential operators in the context of contact geometry. I have some knowledge of pseudodifferential operators on ...
user93630's user avatar
3 votes
1 answer
276 views

Decreasing the binding number of an open book while increasing the genus of the pages

Let $(B,\pi)$ be an open book decomposition of a closed, connected, oriented 3-manifold $M$ with odd (even) binding number and with pages of Euler characteristic $\chi$. Is it possible to define ...
Mustafa's user avatar
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4 votes
2 answers
219 views

Is $\mathbb{P}T^*M$ a sub-Riemannian manifold if $M$ is Riemannian?

(this question is about a particular aspect of a previous question, which was not duly stressed) Let $(M,g)$ a Riemannian $n$-dimensional manifold, and let $$ \widetilde{M}:=\mathbb{P}T^*M $$ be the $...
Giovanni Moreno's user avatar
7 votes
0 answers
201 views

Biholomorphic neighborhoods of the boundary of Stein domains

Let $(X_1,J_1)$ and $(X_2,J_2)$ be Stein domains with the same contact boundary $(Y,\xi)$. Under what conditions does there exist a biholomorphism between a neighborhood of their respective boundaries ...
PVAL's user avatar
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9 votes
2 answers
613 views

Contact distributions on $(G_2,P)$-type Cartan geometries in dimension 5

Up to topology, the 5D homogeneous space $$ G_2/P $$ of the (real form of the) 14D exceptional Lie group $G_2$ is the 5D jet space $$ M:=J^1(2,1)=\{(x,y,u,p,q)\} $$ of scalar functions in two ...
Giovanni Moreno's user avatar
3 votes
1 answer
212 views

How many second-order PDEs can be obtained from a contact EDS?

Let $(M,[\theta])$ be a contact manifold, $\dim M=2n+1$, and denote by $\mathcal{I}^\theta$ the differential ideal generated by the contact form $\theta$. An exterior differential system on $M$ of ...
Giovanni Moreno's user avatar
1 vote
2 answers
630 views

Contact and CR Examples

What is an example of a manifold such that: (A) It is both a contact manifold and a CR manifold (B) It is a contact manifold but not a CR manifold (C) It is not a contact manifold but not a CR ...
Todd Johnson's user avatar
6 votes
2 answers
434 views

Symplectic orthogonality and projective duality: how do they work together?

Let $(V,\omega)$ be a $2n$-dimensional linear symplectic space, and $(\mathbb{P}V,\theta_\omega)$ the corresponding $(2n-1)$-dimensional contact manifold. Given a smooth $(n-1)$-dimensional smooth ...
Giovanni Moreno's user avatar
6 votes
1 answer
423 views

stabilization of Legendrian knots

There are two ways to stabilize a Legendrian knot $k$ in standard contact sphere $(S^3,\xi_{st})$ i.e. adding right cusps or left cusps, let's call these two stabilized Legendrian knots $k_R$ and $k_{...
nikita's user avatar
  • 1,335
4 votes
1 answer
200 views

Does a $G$-structure on $M$ automatically descend to a contact $G$-structure on $\mathbb{P}T^*M$?

If $M$ is a real smooth manifold of dimension $n+1$, by $D\in\mathbb{P}T^*M$ I mean a tangent hyperplane at some point of $M$. I denote by $b$ the canonical projection of the $(2n+1)$-dimensional ...
Giovanni Moreno's user avatar