{"title":"Additional symmetries for the N=2 supersymmetric Two-Boson hierarchy and the multi-component generalization","authors":"Jian Li , Chuanzhong Li","doi":"10.1016/j.geomphys.2025.105455","DOIUrl":"10.1016/j.geomphys.2025.105455","url":null,"abstract":"<div><div>In this paper, we primarily define the N=2 supersymmetric Two-Boson integrable system using N=2 quantum superfields and introduce time variables derived from a non-abelian Lie superalgebra. We construct additional symmetries for the N=2 supersymmetric Two-Boson hierarchy through the Orlov-Schulman operator, which depend on the time variables and the dressing operator. Furthermore, we establish a relationship between the supersymmetric integrable system of N=2 quantum superfields and the Lie superalgebra. Finally, we extend the N=2 supersymmetric Two-Boson hierarchy to the multi-component case and construct the corresponding additional symmetries for it.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"211 ","pages":"Article 105455"},"PeriodicalIF":1.6,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438172","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":"Separation of variables for the Clebsch model: so(4) spectral/separation curves","authors":"T. Skrypnyk","doi":"10.1016/j.geomphys.2025.105453","DOIUrl":"10.1016/j.geomphys.2025.105453","url":null,"abstract":"<div><div>In the present paper we construct symmetric separation of variables (SoV) for the anisotropic Clebsch model for which both curves of separation coincide with spectral curve <span><math><mi>K</mi></math></span> of its <span><math><mi>s</mi><mi>o</mi><mo>(</mo><mn>4</mn><mo>)</mo></math></span>-valued Lax matrix. We explicitly construct coordinates and momenta of separation, Abel-type quadratures and reconstruction formulae for the presented new SoV. The found SoV is the first example of SoV for integrable systems with generic <span><math><mi>s</mi><mi>o</mi><mo>(</mo><mi>n</mi><mo>)</mo></math></span>-valued Lax matrices when all curves of separation coincide with a spectral curve of the corresponding <span><math><mi>s</mi><mi>o</mi><mo>(</mo><mi>n</mi><mo>)</mo></math></span>-valued Lax matrix and <span><math><mi>n</mi><mo>></mo><mn>3</mn></math></span>.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"212 ","pages":"Article 105453"},"PeriodicalIF":1.6,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143510384","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":"Local systems of Castelnuovo-type and factorization of semistable families","authors":"Luca Rizzi , Francesco Zucconi","doi":"10.1016/j.geomphys.2025.105452","DOIUrl":"10.1016/j.geomphys.2025.105452","url":null,"abstract":"<div><div>We show the Castelnuovo-de Franchis Theorem for local systems of relative one forms. Thanks to this result we prove a factorization theorem for semistable families up to base change and we find conditions ensuring that the factorizing variety is a product. As a byproduct, we give a characterization of maximal rationally connected fibrations in the relative setting.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"211 ","pages":"Article 105452"},"PeriodicalIF":1.6,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465431","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":"Constantly curved holomorphic two-spheres in the complex Grassmannian G(2,6) with constant square norm of the second fundamental form","authors":"Jie Fei , Ling He , Jun Wang","doi":"10.1016/j.geomphys.2025.105451","DOIUrl":"10.1016/j.geomphys.2025.105451","url":null,"abstract":"<div><div>We completely classify all noncongruent linearly full totally unramified constantly curved holomorphic two-spheres in <span><math><mi>G</mi><mo>(</mo><mn>2</mn><mo>,</mo><mn>6</mn><mo>)</mo></math></span> with constant square norm of the second fundamental form. They turn out to be homogeneous.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"211 ","pages":"Article 105451"},"PeriodicalIF":1.6,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428078","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 purely analytic derivation of Bonnet surfaces","authors":"Robert Conte , Alfred Michel Grundland","doi":"10.1016/j.geomphys.2025.105454","DOIUrl":"10.1016/j.geomphys.2025.105454","url":null,"abstract":"<div><div>Bonnet has characterized his surfaces by a geometric condition. What is done here is a characterization of the same surfaces by two analytic conditions: (i) the mean curvature <em>H</em> of a surface in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>3</mn></mrow></msup></math></span> should admit a reduction to an ordinary differential equation; (ii) this latter equation should possess the Painlevé property.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"211 ","pages":"Article 105454"},"PeriodicalIF":1.6,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454137","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}
Ángel González-Prieto , Márton Hablicsek , Jesse Vogel
{"title":"Virtual classes of character stacks","authors":"Ángel González-Prieto , Márton Hablicsek , Jesse Vogel","doi":"10.1016/j.geomphys.2025.105450","DOIUrl":"10.1016/j.geomphys.2025.105450","url":null,"abstract":"<div><div>In this paper, we extend the Topological Quantum Field Theory developed by González-Prieto, Logares, and Muñoz for computing virtual classes of <em>G</em>-representation varieties of closed orientable surfaces in the Grothendieck ring of varieties to the setting of the character stacks. To this aim, we define a suitable Grothendieck ring of representable stacks, over which this Topological Quantum Field Theory is defined. In this way, we compute the virtual class of the character stack over B<em>G</em>, that is, a motivic decomposition of the representation variety with respect to the natural adjoint action.</div><div>We apply this framework in two cases providing explicit expressions for the virtual classes of the character stacks of closed orientable surfaces of arbitrary genus. First, in the case of the affine linear group of rank 1, the virtual class of the character stack fully remembers the natural adjoint action, in particular, the virtual class of the character variety can be straightforwardly derived. Second, we consider the non-connected group <span><math><msub><mrow><mi>G</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>⋊</mo><mi>Z</mi><mo>/</mo><mn>2</mn><mi>Z</mi></math></span>, and we show how our theory allows us to compute motivic information of the character stacks where the classical naïve point-counting method fails.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"211 ","pages":"Article 105450"},"PeriodicalIF":1.6,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The generic étaleness of the moduli space of dormant so2ℓ-opers","authors":"Yasuhiro Wakabayashi","doi":"10.1016/j.geomphys.2025.105439","DOIUrl":"10.1016/j.geomphys.2025.105439","url":null,"abstract":"<div><div>The generic étaleness is an important property on the moduli space of dormant <span><math><mi>g</mi></math></span>-opers (for a simple Lie algebra <span><math><mi>g</mi></math></span>) in the context of enumerative geometry. In the previous study, this property has been verified under the assumption that <span><math><mi>g</mi></math></span> is either <span><math><msub><mrow><mi>sl</mi></mrow><mrow><mi>ℓ</mi></mrow></msub></math></span>, <span><math><msub><mrow><mi>so</mi></mrow><mrow><mn>2</mn><mi>ℓ</mi><mo>−</mo><mn>1</mn></mrow></msub></math></span>, or <span><math><msub><mrow><mi>sp</mi></mrow><mrow><mn>2</mn><mi>ℓ</mi></mrow></msub></math></span> for any sufficiently small positive integer <em>ℓ</em>. The purpose of the present paper is to prove the generic étaleness for one of the remaining cases, i.e., <span><math><mi>g</mi><mo>=</mo><msub><mrow><mi>so</mi></mrow><mrow><mn>2</mn><mi>ℓ</mi></mrow></msub></math></span>. As an application of this result, we obtain a factorization formula for computing the generic degree induced from pull-back along various clutching morphisms between moduli spaces of pointed stable curves.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"211 ","pages":"Article 105439"},"PeriodicalIF":1.6,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396035","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":"Local realizations of vertex algebras","authors":"Peng Wang, Liangyun Chen","doi":"10.1016/j.geomphys.2025.105440","DOIUrl":"10.1016/j.geomphys.2025.105440","url":null,"abstract":"<div><div>In this paper, we mainly construct local realizations of vertex algebras for building bridges between vertex algebras and geometries. First, construct an associative algebra which we call Psi algebra that can equip the structure of any vertex algebra, and give a useful action of Psi algebra that can inherit the information of Borcherds' identities. Next, by using the path algebra and the representations of a quiver which is taken according to Psi algebra, we show a type of local realizations for any vertex algebra. Then, we give an approach to realizations of finite-dimensional vector spaces by quiver Grassmannians. Further, we can also use quiver Grassmannians to show another type of local realizations for any vertex algebra by this approach.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"211 ","pages":"Article 105440"},"PeriodicalIF":1.6,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396034","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":"Relating Hamiltonian systems with multiple invariants to generalized Hamiltonian mechanics via multisymplectic geometry","authors":"Nathan Duignan , Naoki Sato","doi":"10.1016/j.geomphys.2025.105438","DOIUrl":"10.1016/j.geomphys.2025.105438","url":null,"abstract":"<div><div>Classical Hamiltonian mechanics, characterized by a single conserved Hamiltonian (energy) and symplectic geometry, ‘hides’ other invariants into symmetries of the Hamiltonian or into the kernel of the Poisson tensor. Nambu mechanics aims to generalize classical Hamiltonian mechanics to ideal dynamical systems bearing two Hamiltonians, but its connection to a suitable geometric framework has remained elusive. This work establishes a novel correspondence between generalized Hamiltonian mechanics, defined for systems with a phase space conservation law (invariance of a closed form) and a matter conservation law (invariance of multiple Hamiltonians), and classical Hamiltonian mechanics via multisymplectic geometry. The key lies in the invertibility of differential forms of degree higher than 2. We demonstrate that the cornerstone theorems of classical Hamiltonian mechanics (Lie-Darboux and Liouville) require reinterpretation within this new framework, reflecting the unique properties of invertibility in multisymplectic geometry. Furthermore, we present two key theorems that solidify the connection: i) any classical Hamiltonian system with two or more invariants is also a generalized Hamiltonian system and ii) given a generalized Hamiltonian system with two or more invariants, there exists a corresponding classical Hamiltonian system on the level set of all but one invariant, with the remaining invariant playing the role of the Hamiltonian function.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"211 ","pages":"Article 105438"},"PeriodicalIF":1.6,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The three-point Gaudin model and branched coverings of the Riemann sphere","authors":"Natalia Amburg , Ilya Tolstukhin","doi":"10.1016/j.geomphys.2025.105436","DOIUrl":"10.1016/j.geomphys.2025.105436","url":null,"abstract":"<div><div>We study the three-point quantum <span><math><msub><mrow><mi>sl</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> Gaudin model. In this case the compactification of the parameter space is <span><math><mover><mrow><msub><mrow><mi>M</mi></mrow><mrow><mn>0</mn><mo>,</mo><mn>4</mn></mrow></msub><mo>(</mo><mi>C</mi><mo>)</mo></mrow><mo>‾</mo></mover></math></span>, which is the Riemann sphere. We analyze sphere coverings by the joint spectrum of the Gaudin Hamiltonians treating them as algebraic curves. We write equations for these curves as determinants of tridiagonal matrices and deduce some consequences regarding the geometric structure of the Gaudin coverings.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"211 ","pages":"Article 105436"},"PeriodicalIF":1.6,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093360","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}