{"title":"Non-degeneracy of the Hofer norm for Poisson structures","authors":"Duvsan Joksimovi'c, I. Marcut","doi":"10.4310/jsg.2021.v19.n5.a3","DOIUrl":"https://doi.org/10.4310/jsg.2021.v19.n5.a3","url":null,"abstract":"We remark that, as in the symplectic case, the Hofer norm on the Hamiltonian group of a Poisson manifold is non-degenerate. The proof is a straightforward application of tools from symplectic topology.","PeriodicalId":50029,"journal":{"name":"Journal of Symplectic Geometry","volume":"12 15 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90174477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Noncontractible loops of symplectic embeddings between convex toric domains","authors":"M. Munteanu","doi":"10.4310/jsg.2020.v18.n4.a8","DOIUrl":"https://doi.org/10.4310/jsg.2020.v18.n4.a8","url":null,"abstract":"Given two 4-dimensional ellipsoids whose symplectic sizes satisfy a specified inequality, we prove that a certain loop of symplectic embeddings between the two ellipsoids is noncontractible. The statement about symplectic ellipsoids is a particular case of a more general result. Given two convex toric domains whose first and second ECH capacities satisfy a specified inequality, we prove that a certain loop of symplectic embeddings between the two convex toric domains is noncontractible. We show how the constructed loops become contractible if the target domain becomes large enough. The proof involves studying certain moduli spaces of holomorphic cylinders in families of symplectic cobordisms arising from families of symplectic embeddings.","PeriodicalId":50029,"journal":{"name":"Journal of Symplectic Geometry","volume":"2 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77295833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Alekseev, Benjamin Hoffman, J. Lane, Yanpeng Li
{"title":"Concentration of symplectic volumes on Poisson homogeneous spaces","authors":"A. Alekseev, Benjamin Hoffman, J. Lane, Yanpeng Li","doi":"10.4310/JSG.2020.v18.n5.a1","DOIUrl":"https://doi.org/10.4310/JSG.2020.v18.n5.a1","url":null,"abstract":"For a compact Poisson-Lie group $K$, the homogeneous space $K/T$ carries a family of symplectic forms $omega_xi^s$, where $xi in mathfrak{t}^*_+$ is in the positive Weyl chamber and $s in mathbb{R}$. The symplectic form $omega_xi^0$ is identified with the natural $K$-invariant symplectic form on the $K$ coadjoint orbit corresponding to $xi$. The cohomology class of $omega_xi^s$ is independent of $s$ for a fixed value of $xi$. \u0000In this paper, we show that as $sto -infty$, the symplectic volume of $omega_xi^s$ concentrates in arbitrarily small neighbourhoods of the smallest Schubert cell in $K/T cong G/B$. This strengthens earlier results [9,10] and is a step towards a conjectured construction of global action-angle coordinates on $Lie(K)^*$ [4, Conjecture 1.1].","PeriodicalId":50029,"journal":{"name":"Journal of Symplectic Geometry","volume":"22 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80491484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"H-principles for regular Lagrangians","authors":"Oleg Lazarev","doi":"10.4310/jsg.2020.v18.n4.a4","DOIUrl":"https://doi.org/10.4310/jsg.2020.v18.n4.a4","url":null,"abstract":"We prove an existence h-principle for regular Lagrangians with Legendrian boundary in arbitrary Weinstein domains of dimension at least six; this extends a previous result of Eliashberg, Ganatra, and the author for Lagrangians in flexible domains. Furthermore, we show that all regular Lagrangians come from our construction and describe some related decomposition results. We also prove a regular version of Eliashberg and Murphy's h-principle for Lagrangian caps with loose negative end. As an application, we give a new construction of infinitely many regular Lagrangian disks in the standard Weinstein ball.","PeriodicalId":50029,"journal":{"name":"Journal of Symplectic Geometry","volume":"647 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85364694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Iso-contact embeddings of manifolds in co-dimension $2$","authors":"Dishant M. Pancholi, Suhas Pandit","doi":"10.4310/jsg.2022.v20.n2.a3","DOIUrl":"https://doi.org/10.4310/jsg.2022.v20.n2.a3","url":null,"abstract":"The purpose of this article is to study co-dimension $2$ iso-contact embeddings of closed contact manifolds. We first show that a closed contact manifold $(M^{2n-1}, xi_M)$ iso-contact embeds in a contact manifold $(N^{2n+1}, xi_N),$ provided $M$ contact embeds in $(N, xi_N)$ with a trivial normal bundle and the contact structure induced on $M$ via this embedding is homotopic as an almost-contact structure to $xi_M.$ We apply this result to first establish that a closed contact $3$--manifold having no $2$--torsion in its second integral cohomology iso-contact embeds in the standard contact $5$--sphere if and only if the first Chern class of the contact structure is zero. Finally, we discuss iso-contact embeddings of closed simply connected contact $5$--manifolds.","PeriodicalId":50029,"journal":{"name":"Journal of Symplectic Geometry","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73371247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Positive topological entropy of positive contactomorphisms","authors":"Lucas Dahinden","doi":"10.4310/jsg.2020.v18.n3.a3","DOIUrl":"https://doi.org/10.4310/jsg.2020.v18.n3.a3","url":null,"abstract":"A positive contactomorphism of a contact manifold $M$ is the end point of a contact isotopy on $M$ that is always positively transverse to the contact structure. Assume that $M$ contains a Legendrian sphere $Lambda$, and that $(M,Lambda)$ is fillable by a Liouville domain $(W,omega)$ with exact Lagrangian $L$ such that $omega|_{pi_2(W,L)}=0$. We show that if the exponential growth of the action filtered wrapped Floer homology of $(W,L)$ is positive, then every positive contactomorphism of $M$ has positive topological entropy. This result generalizes the result of Alves and Meiwes from Reeb flows to positive contactomorphisms, and it yields many examples of contact manifolds on which every positive contactomorphism has positive topological entropy, among them the exotic contact spheres found by Alves and Meiwes. \u0000A main step in the proof is to show that wrapped Floer homology is isomorphic to the positive part of Lagrangian Rabinowitz-Floer homology.","PeriodicalId":50029,"journal":{"name":"Journal of Symplectic Geometry","volume":"9 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84795003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On linking of Lagrangian tori in $mathbb{R}^4$","authors":"Laurent Cot'e","doi":"10.4310/jsg.2020.v18.n2.a3","DOIUrl":"https://doi.org/10.4310/jsg.2020.v18.n2.a3","url":null,"abstract":"We prove some results about linking of Lagrangian tori in the symplectic vector space $(mathbb{R}^4, omega)$. We show that certain enumerative counts of holomophic disks give useful information about linking. This enables us to prove, for example, that any two Clifford tori are unlinked in a strong sense. We extend work of Dimitroglou Rizell and Evans on linking of monotone Lagrangian tori to a class of non-monotone tori in $mathbb{R}^4$ and also strengthen their conclusions in the monotone case in $mathbb{R}^4$.","PeriodicalId":50029,"journal":{"name":"Journal of Symplectic Geometry","volume":"111 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88060285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Almost-Kähler smoothings of compact complex surfaces with $A_1$ singularities","authors":"Caroline Vernier","doi":"10.4310/jsg.2020.v18.n5.a5","DOIUrl":"https://doi.org/10.4310/jsg.2020.v18.n5.a5","url":null,"abstract":"This paper is concerned with the existence of metrics of constant Hermitian scalar curvature on almost-Kahler manifolds obtained as smoothings of a constant scalar curvature Kahler orbifold, with A1 singularities. More precisely, given such an orbifold that does not admit nontrivial holomorphic vector fields, we show that an almost-Kahler smoothing (Me, ωe) admits an almost-Kahler structure (Je, ge) of constant Hermitian curvature. Moreover, we show that for e > 0 small enough, the (Me, ωe) are all symplectically equivalent to a fixed symplectic manifold (M , ω) in which there is a surface S homologous to a 2-sphere, such that [S] is a vanishing cycle that admits a representant that is Hamiltonian stationary for ge.","PeriodicalId":50029,"journal":{"name":"Journal of Symplectic Geometry","volume":"39 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77696488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A homotopical viewpoint at the Poisson bracket invariants for tuples of sets","authors":"Y. Ganor","doi":"10.4310/jsg.2020.v18.n4.a2","DOIUrl":"https://doi.org/10.4310/jsg.2020.v18.n4.a2","url":null,"abstract":"We suggest a homotopical description of the Poisson bracket invariants for tuples of closed sets in symplectic manifolds. It implies that these invariants depend only on the union of the sets along with topological data.","PeriodicalId":50029,"journal":{"name":"Journal of Symplectic Geometry","volume":"9 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76753983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Complex analytic properties of minimal Lagrangian submanifolds","authors":"R. Maccheroni","doi":"10.4310/jsg.2020.v18.n4.a6","DOIUrl":"https://doi.org/10.4310/jsg.2020.v18.n4.a6","url":null,"abstract":"In this article we study complex properties of minimal Lagrangian submanifolds in Kaehler ambient spaces, and how they depend on the ambient curvature. In particular, we prove that, in the negative curvature case, minimal Lagrangians do not admit fillings by holomorphic discs. The proof relies on a mix of holomorphic curve techniques and on certain convexity results.","PeriodicalId":50029,"journal":{"name":"Journal of Symplectic Geometry","volume":"62 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2018-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73158464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}