{"title":"Higher order Jacobian matrix theory and invariants of singularities","authors":"Shuanghe Fan,Stephen S.-T. Yau,Huaiqing Zuo","doi":"10.4310/jdg/1789484463","DOIUrl":"https://doi.org/10.4310/jdg/1789484463","url":null,"abstract":"The higher order Nash blow-up of an algebraic variety replaces singular points with limits of certain spaces carrying higher order data associated to the variety at non-singular points. Inspired by the higher order Nash blow-up, we develop higher order Jacobian matrix theory, a generalization of the Jacobian matrix theory in the usual sense. The most significant contribution of this work is the higher order generalization of similarity transformation. It bridges the two long-standing, distinct research directions in the study of higher-order Jacobian matrices: the one from the higher order Nash blowup of a hypersurface, and the one representing a higher-order tangent map of a morphism. As an application, we use it to construct different contact and right invariants of isolated singularities, generalizing the Tjurina algebra and the Milnor algebra in singularity theory respectively. It is worth mentioning that the Tjurina algebra and the Milnor algebra were constructed using first-order derivatives, but now we are constructing invariants using arbitrary higher-order derivatives. The higher order Jacobian matrix theory also has potential applications and inspirations in multiple branches of mathematics: inspiring the establishment of higher order Hessian matrix theory and projective invariants, calculating explicit expression for the inverse of an automorphism of a power series ring, and performing explicit calculations in finite determinacy.","PeriodicalId":15642,"journal":{"name":"Journal of Differential Geometry","volume":"154 1","pages":"217-268"},"PeriodicalIF":2.5,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Antonio Alfieri,Irving Dai,Abhishek Mallick,Masaki Taniguchi
{"title":"Involutions and the Chern-Simons filtration in instanton Floer homology","authors":"Antonio Alfieri,Irving Dai,Abhishek Mallick,Masaki Taniguchi","doi":"10.4310/jdg/1789483138","DOIUrl":"https://doi.org/10.4310/jdg/1789483138","url":null,"abstract":"Building on the work of Nozaki, Sato and Taniguchi, we develop an instanton-theoretic invariant aimed at studying strong corks and equivariant bounding. Our construction utilizes the Chern-Simons filtration and is qualitatively different from previous Floer-theoretic methods used to address these questions. As an application, we give an example of a cork whose boundary involution does not extend over any 4-manifold $X$ with $H_1left(X, mathbb{Z}_2right)=0$ and $b_2(X) leq 1$, and a strong cork which survives stabilization by either of $n mathbb{C P}^2$ or $n overline{mathbb{C P}}^2$. We also prove that every nontrivial linear combination of $1 / n$-surgeries on the strongly invertible knot $overline{9}_{46}$ constitutes a strong cork. Although Yang-Mills theory has been used to study corks via the Donaldson invariant, this is the first instance where the critical values of the Chern-Simons functional have been utilized to produce such examples. Finally, we discuss the geography question for nonorientable surfaces in the case of extremal normal Euler number.","PeriodicalId":15642,"journal":{"name":"Journal of Differential Geometry","volume":"1 1","pages":"137-215"},"PeriodicalIF":2.5,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149021098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A new Poincaré type rigidity phenomenon with applications","authors":"Ming Xiao","doi":"10.4310/jdg/1788448633","DOIUrl":"https://doi.org/10.4310/jdg/1788448633","url":null,"abstract":"We discover a new Poincaré type phenomenon by establishing an optimal rigidity theorem for local CR (Cauchy-Riemann) mappings between circle bundles that are defined in a canonical way over (possibly reducible) bounded symmetric domains. We prove such a local CR map, if nonconstant, must extend to a rational biholomorphism between the corresponding disk bundles. The result includes as a special case the classical Poincaré-Tanaka-Alexander theorem. Among other applications, we show, for two irreducible bounded symmetric domains with rank at least two, a local CR diffeomorphism between (open connected pieces of) their anti-canonical circle bundles extends to a norm-preserving holomorphic isomorphism between their anti-canonical bundles. The statement fails in the rank one case. As another application, we construct, for any $n geq 2$, a countably infinite family of compact locally homogeneous strongly pseudoconvex CR hypersurfaces (in complex manifolds) of real dimension $2 n+1$ with transverse symmetry such that they are all obstruction flat and Bergman logarithmically flat. Moreover, their local CR structures are mutually inequivalent. Such a family cannot exist in dimension three by known results: A Bergman logarithmically flat CR hypersurface must be spherical, and so is a compact obstruction flat CR hypersurface with transverse symmetry.","PeriodicalId":15642,"journal":{"name":"Journal of Differential Geometry","volume":"379 1","pages":"97-135"},"PeriodicalIF":2.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148894744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Realization of tropical curves in Abelian surfaces","authors":"Takeo Nishinou","doi":"10.4310/jdg/1788448114","DOIUrl":"https://doi.org/10.4310/jdg/1788448114","url":null,"abstract":"We construct algebraic curves in abelian surfaces by utilizing tropical curves in real tori. We give a necessary and sufficient condition for a tropical curve in a real torus to be realizable by an algebraic curve in an abelian surface. When this condition is satisfied, the number of algebraic curves can be computed by a combinatorial formula. This provides the algebraic-tropical correspondence theorem for abelian surfaces analogous to Mikhalkin's correspondence theorem for toric surfaces. Thus, the number of algebraic curves passing through generic points in an abelian surface can be computed purely combinatorially via tropical curves.","PeriodicalId":15642,"journal":{"name":"Journal of Differential Geometry","volume":"17 1","pages":"1-95"},"PeriodicalIF":2.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148894745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Conical Calabi–Yau metrics on toric affine varieties and convex cones","authors":"Robert J. Berman","doi":"10.4310/jdg/1696432924","DOIUrl":"https://doi.org/10.4310/jdg/1696432924","url":null,"abstract":"It is shown that any affine toric variety $Y$, which is $mathbb{Q}$-Gorenstein, admits a conical Ricci flat Kähler metric, which is smooth on the regular locus of $Y$. The corresponding Reeb vector is the unique minimizer of the volume functional on the Reeb cone of $Y$. The case when the vertex point of $Y$ is an isolated singularity was previously shown by Futaki–Ono–Wang. The proof is based on an existence result for the inhomogeneous Monge–Ampère equation in $mathbb{R}^m$ with exponential right hand side and with prescribed target given by a proper convex cone, combined with transversal a priori estimates on $Y$.","PeriodicalId":15642,"journal":{"name":"Journal of Differential Geometry","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135948526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The index formula for families of Dirac type operators on pseudomanifolds","authors":"Pierre Albin, Jesse Gell-Redman","doi":"10.4310/jdg/1696432923","DOIUrl":"https://doi.org/10.4310/jdg/1696432923","url":null,"abstract":"We study families of Dirac-type operators, with compatible perturbations, associated to wedge metrics on stratified spaces. We define a closed domain and, under an assumption of invertible boundary families, prove that the operators are self-adjoint and Fredholm with compact resolvents and trace-class heat kernels. We establish a formula for the Chern character of their index.","PeriodicalId":15642,"journal":{"name":"Journal of Differential Geometry","volume":"236 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135948774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Existence of multiple closed CMC hypersurfaces with small mean curvature","authors":"Akashdeep Dey","doi":"10.4310/jdg/1696432925","DOIUrl":"https://doi.org/10.4310/jdg/1696432925","url":null,"abstract":"Min-max theory for constant mean curvature (CMC) hypersurfaces has been developed by Zhou–Zhu $[href{https://doi.org/10.1007/s00222-019-00886-1}{39}]$ and Zhou $[href{https://doi.org/10.4007/annals.2020.192.3.3}{38}]$. In particular, in $[href{https://doi.org/10.1007/s00222-019-00886-1}{39}]$, Zhou and Zhu proved that for any $c gt 0$, every closed Riemannian manifold $(M^{n+1}, g), 3 leq n + 1 leq 7$, contains a closed $c$-CMC hypersurface. In this article we will show that the min-max theory for CMC hypersurfaces in $[href{https://doi.org/10.1007/s00222-019-00886-1}{39}, href{https://doi.org/10.4007/annals.2020.192.3.3}{38}]$ can be extended in higher dimensions using the regularity theory of stable CMC hypersurfaces, developed by Bellettini–Wickramasekera $[href{https://doi.org/10.48550/arXiv.1802.00377}{4}, href{https://doi.org/10.48550/arXiv.1902.09669}{5}]$ and Bellettini–Chodosh–Wickramasekera $[href{https://doi.org/10.1016/j.aim.2019.05.023}{3}]$. Furthermore, we will prove that the number of closed $c$-CMC hypersurfaces in a closed Riemannian manifold $(M^{n+1}, g), n+1 geq 3$, tends to infinity as $c to 0^+$. More quantitatively, there exists a constant $gamma_0$, depending on $g$, such that for all $c gt 0$, there exist at least $gamma_0 c^{-frac{1}{n+1}}$ many closed $c$-CMC hypersurfaces (with optimal regularity) in $(M,g)$.","PeriodicalId":15642,"journal":{"name":"Journal of Differential Geometry","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135948783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kwokwai Chan, Naichung Conan Leung, Ziming Nikolas Ma
{"title":"Geometry of the Maurer-Cartan equation near degenerate Calabi-Yau varieties","authors":"Kwokwai Chan, Naichung Conan Leung, Ziming Nikolas Ma","doi":"10.4310/jdg/1695236591","DOIUrl":"https://doi.org/10.4310/jdg/1695236591","url":null,"abstract":"Given a degenerate Calabi–Yau variety $X$ equipped with local deformation data, we construct an almost differential graded Batalin–Vilkovisky algebra $PV^{ast,ast}(X)$, producing a singular version of the extended Kodaira–Spencer differential graded Lie algebra in the Calabi–Yau setting. Assuming Hodge-to-de Rham degeneracy and a local condition that guarantees freeness of the Hodge bundle, we prove a Bogomolov–Tian–Todorov–type unobstructedness theorem for smoothing of singular Calabi–Yau varieties. In particular, this provides a unified proof for the existence of smoothing of both $d$-semistable log smooth Calabi–Yau varieties (as studied by Friedman [$href{https://doi.org/10.2307/2006955}{22}$] and Kawamata–Namikawa [$href{ https://doi.org/10.1007/BF01231538}{41}$]) and maximally degenerate Calabi–Yau varieties (as studied by Kontsevich–Soibelman $[href{ https://link.springer.com/chapter/10.1007/0-8176-4467-9_9}{45}$] and Gross–Siebert [$href{ http://doi.org/10.4007/annals.2011.174.3.1}{30}$]). We also demonstrate how our construction yields a logarithmic Frobenius manifold structure on a formal neighborhood of $X$ in the extended moduli space by applying the technique of Barannikov–Kontsevich [$href{https://doi.org/10.1155/S1073792898000166}{2}$, $href{https://doi.org/10.48550/arXiv.math/9903124}{1}$].","PeriodicalId":15642,"journal":{"name":"Journal of Differential Geometry","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135388033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Harmonic maps from $S^3$ into $S^2$ with low Morse index","authors":"Tristan Rivière","doi":"10.4310/jdg/1695236594","DOIUrl":"https://doi.org/10.4310/jdg/1695236594","url":null,"abstract":"We prove that any smooth harmonic map from $S^3$ into $S^2$ of Morse index less or equal than $4$ has to be an harmonic morphism, that is the successive composition of an isometry of $S^3$, the Hopf fibration and an holomorphic map from $mathbb{C}P^1$ into itself.","PeriodicalId":15642,"journal":{"name":"Journal of Differential Geometry","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135388385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On number and evenness of solutions of the $SU(3)$ Toda system on flat tori with non-critical parameters","authors":"Zhijie Chen, Chang-Shou Lin","doi":"10.4310/jdg/1695236592","DOIUrl":"https://doi.org/10.4310/jdg/1695236592","url":null,"abstract":"We study the $SU(3)$ Toda system with singular sources begin{equation*} begin{cases} Delta u+2e^{u}-e^{v}=4pi sum _{k=0}^{m} n_{1,k}delta _{p_{k}} quad text{ on }; E_{tau}, Delta v+2e^{v}-e^{u}=4pi sum _{k=0}^{m} n_{2,k}delta _{p_{k}} quad text{ on }; E_{tau}, end{cases} end{equation*} where $E_{tau}:=mathbb{C}/(mathbb{Z}+mathbb{Z}tau )$ with $operatorname{Im}tau gt 0$ is a flat torus, $delta _{p_{k}}$ is the Dirac measure at $p_{k}$, and $n_{i,k}in mathbb{Z}_{geq 0}$ satisfy $sum _{k}n_{1,k}not equiv sum _{k} n_{2,k} mod 3$. This is known as the non-critical case and it follows from a general existence result of [$href{ https://doi.org/10.1016/j.aim.2015.07.036}{3}$] that solutions always exist. In this paper we prove that (i) The system has at most begin{equation*} frac{1}{3times 2^{m+1}}prod _{k=0}^{m}(n_{1,k}+1)(n_{2,k}+1)(n_{1,k}+n_{2,k}+2) in mathbb{N} end{equation*} solutions. We have several examples to indicate that this upper bound should be sharp. Our proof presents a nice combination of the apriori estimates from analysis and the classical Bézout theorem from algebraic geometry. (ii) For $m=0$ and $p_{0}=0$, the system has even solutions if and only if at least one of ${n_{1,0}, n_{2,0}}$ is even. Furthermore, if $n_{1,0}$ is odd, $n_{2,0}$ is even and $n_{1,0}lt n_{2,0}$, then except for finitely many $tau $’s modulo $SL(2,mathbb{Z})$ action, the system has exactly $frac{n_{1,0}+1}{2}$ even solutions. Differently from [$href{ https://doi.org/10.1016/j.aim.2015.07.036}{3}$], our proofs are based on the integrability of the Toda system, and also imply a general non-existence result for even solutions of the Toda system with four singular sources.","PeriodicalId":15642,"journal":{"name":"Journal of Differential Geometry","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135388235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}