In this paper, we study deformations of compact holomorphic Poisson submanifolds which extend Kodaira's series of papers on semi-regularity (deformations of compact complex submanifolds of codimension 1), deformations of compact complex submanifolds of arbitrary codimensions, and stability of compact complex submanifol…
In this article, we consider Cayley deformations of a compact complex surface in a Calabi--Yau four-fold. We will study complex deformations of compact complex submanifolds of Calabi--Yau manifolds with a view to explaining why complex and Cayley deformations of a compact complex surface are the same. We in fact prove …
Study deformations of compact Kähler hyperbolic manifolds.
problem Investigate the deformation openness of Kähler hyperbolicity.
method Propose modified versions of Kähler hyperbolicity as a tool.
result Provide a first step towards understanding deformations.
In this thesis, we study deformations of compact holomorphic Poisson manifolds and algebraic Poisson schemes in the framework of Kodaira-Spencer's analytic deformation theory and Grothendieck's algebraic deformation theory.
Study deformations of compact Calabi-Yau conifolds with singularities.
problem Understanding deformations of compact Calabi-Yau conifolds with singularities.
method Analyzes the obstructions and local triviality of deformations under specific topological and geometric hypotheses.
result Obstruction to deformations concentrates at singularities, generalizing previous results.
The paper extends Witten's deformation to foliations and Morse functions.
problem Extending Witten's deformation to foliations and Morse functions.
method Using deformation to the normal cone and C*-modules, the paper constructs the Witten deformation for generic functions on foliations.
result Establishes the compactness of the resolvent and Morse inequalities for foliations with invariant transverse measures.
The paper constructs metrics on compact manifolds using Aubin's deformations.
problem Existence of metrics with non-vanishing Weyl tensor on compact manifolds.
method Special metric deformations introduced by Aubin.
result Existence of metrics with non-vanishing Weyl tensor on compact manifolds, no topological obstructions in dimension four.
We combine classic stability results for foliations with recent results on deformations of Lie groupoids and Lie algebroids to provide a cohomological characterization for rigidity of compact foliations on compact manifolds.
Study on a deformed Hermitian-Yang-Mills equation on compact Kähler manifolds.
problem Existence of solutions to the hypercritical deformed Hermitian-Yang-Mills equation.
method Introduce coerciveness and properness of the J-functional on almost calibrated (1,1)-forms.
result Equivalence of coerciveness and properness to the existence of solutions.
The paper studies deformations of cohesive modules on complex manifolds.
problem Deformation theory of cohesive modules on compact complex manifolds.
method Development of Kuranishi maps and obstructions for deformations of cohesive modules.
result Generalization of deformation theory for holomorphic vector bundles and coherent sheaves.
Develops a method to deform metrics on manifolds with non-compact boundaries.
problem Creating metrics with positive scalar curvature on manifolds with boundary.
method General deformation principle for Riemannian metrics on manifolds with non-compact boundaries.
result Non-existence of metrics with positive scalar curvature and mean convex boundary.
Study on deforming calibrated submanifolds with boundary constraints.
problem Deforming calibrated submanifolds with boundary constraints in Riemannian manifolds.
method Extends McLean's deformation theory for closed compact submanifolds to include boundaries.
result Results extend McLean's theory to include boundaries, allowing for more flexible submanifold deformations.
Study on deformations of symmetric spaces using Jordan algebras.
problem Deformability of symmetric Einstein metrics on compact Lie algebras.
method Developed sandwich operators and quadratic Casimir operators for compact Lie algebras; calculated obstruction integrals from invariant polynomials; explored relation to simple Jordan algebras.
result Proved the nonlinear instability of most infinitesimally deformable irreducible compact symmetric spaces.
Study resolves conjectures on hypercritical deformed Hermitian-Yang-Mills equation.
problem Resolving conjectures on hypercritical deformed Hermitian-Yang-Mills equation.
method Study compact Kähler manifolds and resolves conjectures of Collins-Yau.
result Resolves two conjectures of Collins-Yau.
We introduce K-deformations of generalized complex structures on a compact Kahler manifold M=(X,J) with an effective anti-canonical divisor and show that obstructions to K-deformations of generalized complex structures on M always vanish. Applying the stability theorem of generalized Kahler structures, together wi…
In this paper, we prove several formulas related to Hodge theory, and using them to prove the deformations of a compact H-twisted generalized Calabi-Yau manifold are unobstructed and L2 convergence in a neighborhood in another power series . And if we assume that the deformation is smooth in a fixed neighborhood, …
Researchers derived heat kernel expansions for non-compact spaces using Witten deformation.
problem Heat kernel expansions on non-compact spaces, especially for Witten Laplacians.
method Introduced parabolic distance and used it to derive asymptotic expansions.
result Derived an asymptotic expansion of trace of heat kernel for small-time t. Study of deformed Bott-Chern cohomology on complex manifolds.
problem Deformation theory and cohomology of complex manifolds.
method Introduce a double complex structure and study its Bott-Chern cohomology.
result Established a deformation theory for Bott-Chern cohomology and computed deformed cohomology for specific manifolds.
The study explores deformations of discrete subgroups in non-compact homogeneous spaces.
problem Addressing the proper discontinuity of discrete subgroups in non-compact homogeneous spaces.
method Classification results for deformations of standard discontinuous groups in pseudo-Riemannian homogeneous spaces.
result Conditions for local rigidity and Zariski-dense deformations in standard quotients.
Compact hyperbolic complex manifolds are rigid under deformation.
problem Studying the deformation behavior of compact hyperbolic complex manifolds.
method Analyzing smooth families of compact complex manifolds over the unit disk and compact Riemann surfaces.
result The H-locus is either at most a discrete subset or the whole domain, depending on the family structure. This paper shows similarities in deformation spaces of Kleinian groups and anti-holomorphic maps.
problem Comparing deformation spaces of Kleinian reflection groups and anti-holomorphic rational maps.
method Established an analogue of Thurston's compactness theorem for critically fixed anti-rational maps and characterized deformation space interactions.
result Deformation spaces of Kleinian reflection groups and anti-holomorphic rational maps share striking similarities.
Compact metric f-K-contact manifolds constructed via specific transformations.
problem Constructing all metric f-K-contact manifolds.
method Iteration of constructions of mapping tori, rotations, and type II deformations.
result Compact metric f-K-contact manifolds are derived from compact K-contact manifolds.
Study shows compact Sasakian manifolds are locally Heisenberg up to deformation.
problem Characterizing compact Sasakian manifolds.
method Analyzing basic Chern classes and using left invariant Sasakian structures.
result Compact Sasakian manifolds are locally isomorphic to the real Heisenberg group.
In this note we prove that, under a weak condition, small deformations of a compact balanced manifold are also balanced. This condition is satisfied on the twistor space over a compact self-dual four manifold.
Solves supercritical dHYM on projective manifolds with specific conditions.
problem Solving supercritical deformed Hermitian Yang-Mills equation on compact projective manifolds.
method Extends Gao Chen's result to non-constant twisting functions, proving solvability under certain conditions.
result Solvability of the twisted supercritical dHYM equation on compact projective manifolds.
Obstructing deformations of vector forms on Kähler manifolds.
problem Deformations of vector forms on compact Kähler manifolds.
method Annihilating obstruction classes by cohomology classes.
result Obstruction classes are annihilated by cohomology classes.
Localized deformation of scalar curvature and mean curvature on manifolds.
problem Deforming scalar curvature and mean curvature on compact manifolds with boundary.
method Proving localized surjection of scalar curvature and mean curvature map, handling non-variational linearized problem.
result Localized deformations of scalar curvature and mean curvature on compact manifolds are possible.
New method deforms function algebras on manifolds using spectral decomposition.
problem Deforming function algebras on compact Riemannian manifolds.
method Introducing a bilinear product on the finite spectral core of smooth functions using unimodular phases.
result The product extends to a Sobolev algebra and admits iteration under certain conditions.
Study curvatures on compact pseudo-Hermitian manifolds using special methods.
problem Prescribing Webster scalar curvatures on compact pseudo-Hermitian manifolds.
method Upper and lower solutions, perturbation theory of self-adjoint operators, CR conformal deformations.
result Described sets of Webster scalar curvature functions that can be realized.
The paper studies deformations of symplectic forms and Lagrangian submanifolds.
problem Understanding small changes in symplectic forms and their impact on Lagrangian submanifolds.
method Analyzes deformations of the pair (ω, L) using relative de Rham cohomology.
result The moduli space of deformations is smooth and finite-dimensional.
Let G be a noncompact real algebraic group and $\G<G$ a lattice. One purpose of this paper is to show that there is an smooth, volume preserving, mixing action of G or $\G$ on a compact manifold which admits a smooth deformation. We also describe some other, rather special, deformations when G=SO(1,n) and provide…
The paper studies deformations of astheno-Kähler metrics on complex manifolds.
problem Stability of astheno-Kähler metrics under complex structure deformations.
method Proves necessary cohomological conditions for astheno-Kähler metrics along deformations.
result Provides obstructions to the existence of astheno-Kähler metrics on specific nilmanifolds.
We study infinitesimal Einstein deformations on compact flat manifolds and on product manifolds. Moreover, we prove refinements of results by Koiso and Bourguignon which yield obstructions on the existence of infinitesimal Einstein deformations under certain curvature conditions.
Study deformed Hermitian-Yang-Mills equation on complex projective space blowup.
problem Solving the deformed Hermitian-Yang-Mills equation on complex projective space blowup.
method Expressed the equation as an ODE and solved it using combinatorial methods under an algebraic stability condition.
result Evidence supporting a conjecture on general compact Kahler manifolds.
Let X be a compact quotient of the product of the real Heisenberg group H4m+1 of dimension 4m+1 and the 3-dimensional real Euclidean space $\bR^3$. A left invariant hypercomplex structure on $H_{4m+1}\times \bR^3$ descends onto the compact quotient X. The space X is a hyperholomorphic fibration of 4-tori o…
Deformations of compact Riemann surfaces are considered using a Čech cohomology sliding overlaps approach. Cocycles are calculated for conformal cutting and regluing deformations at zeros of Abelian differentials. A second order deformation expansion is presented for the Riemann period matrix. A complete deformation ex…
Deformations of singular Cayley submanifolds studied.
problem Constructing fibrations of compact Spin(7) manifolds.
method Deformation theory of conically singular and asymptotically conical Cayley submanifolds.
result Detailed description of the deformation theory.
For arbitrary compact quantizable Kaehler manifolds it is shown how a natural formal deformation quantization (star product) can be obtained via Berezin-Toeplitz operators. Results on their semi-classical behaviour (their asymptotic expansion) due to Bordemann, Meinrenken and Schlichenmaier are used in an essential man…
The paper proves stability for contact groupoids and deformations.
problem Stability of contact groupoids and deformations.
method Proof of Gray stability for compact contact groupoids.
result Stability results for deformations of induced Jacobi bundles.
Suppose that a compact quantum group Q acts faithfully and isomet- rically (in the sense of [10]) on a smooth compact, oriented, connected Riemannian manifold M . If the manifold is stably parallelizable then it is shown that the compact quantum group is necessarily commutative as a C \ast algebra i.e. Q = C(G) for som…
Study second-order obstruction to nearly G2 structure deformations.
problem Proper nearly G2 structure rigidity on Aloff-Wallach space. method Second-order obstruction analysis, building on Alexandrov and Semmelmann work.
result Proves rigidity for nearly G2 structure on N(1,1). Study on symplectic structures and their deformations.
problem Preservation of complex symplectic structures under deformations.
method Analyzes various cohomologies and conditions for deformations.
result Obtains topological obstructions for compact complex symplectic manifolds.
New CR-structures lemma simplifies CR-manifold deformation proof.
problem Deformation unobstructedness of CR-manifolds.
method New Tian-Todorov lemma applied to CR-manifolds.
result Reproved deformation unobstructedness of CR-manifolds.
By using Klein's model for hyperbolic geometry, hyperbolic structures on orbifolds or manifolds provide examples of real projective structures. By Andreev's theorem, many 3-dimensional reflection orbifolds admit a finite volume hyperbolic structure, and such a hyperbolic structure is unique. However, the induced real p…
In this article, I prove the following statement: Every compact complex surface with even first Betti number is deformation equivalent to one which admits an extremal Kähler metric. In fact, this extremal Kähler metric can even be taken to have constant scalar curvature in all but two cases: the deformation equivalence…
The paper improves embedding results for CR submanifolds, showing that compact deformations stay embeddable.
problem Embedding compactly supported deformations of CR submanifolds in Cn+d. method Proving new embedding results for compactly supported CR deformations of 2-pseudoconcave CR submanifolds. result Compact deformations of 2-pseudoconcave CR submanifolds stay embeddable in Cn+d. McLean studied the deformations of compact special Lagrangian submanifolds, showing in particular that they come in moduli spaces whose dimension depends only on the topology of the submanifold. In this article we study the analogous problem for non-compact, "asymptotically conical" SL submanifolds, with respect to var…
Study disproves conjecture about Hermitian-Yang-Mills solutions.
problem Disproving conjecture about Hermitian-Yang-Mills solutions.
method Analyzes real (1,1)-classes on compact Kähler manifolds.
result Proves conjecture is false by showing proper subset.