A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.
Paper constructs an example of a non-compact submanifold in a quaternionic Kähler symmetric space.
For compact Kählerian manifolds, the holomorphic pseudosymmetry reduces to the local symmetry if additionally the scalar curvature is constant and the structure function is non-negative. Similarly, the holomorphic Ricci-pseudosymmetry reduces to the Ricci-symmetry under these additional assumptions. We construct exampl…
The paper proves conditions for compact complex manifolds to be Kahler outside analytic subsets.
Article is devoted to the Examples 2 and 3 of the symplectic solvable Lie groups with some special cohomological properties, which have been constructed by Benson and Gordon. But they are not succeeded in constructing corresponding compact forms for symplectic structures on these Lie groups. Recently A.Tralle prove…
We survey some results and questions about free actions of infinite groups on products of spheres and euclidean spaces, and give some new co-compact examples.
Small Nijenhuis tensor found on compact manifolds.
Using the Hard Lefschetz Theorem for Sasakian manifolds, we find two examples of compact K-contact nilmanifolds with no compatible Sasakian metric in dimensions five and seven, respectively
3D spaces without boundaries are found that aren't manifolds.
New compact ECS manifolds with rank 2 discovered, differing from previous rank 1 examples.
New examples of isoparametric families on non-compact symmetric spaces.
The notion of a complex hyperpolar action on a symmetric space of non-compact type has recently been introduced as counterpart of a hyperpolar action on a symmetric space of compact type. In this paper, we construct examples of a complex hyperpolar action without singular orbit and investigate the geometry of the orbit…
New metrics found on non-Kähler Calabi-Yau manifolds.
Explains examples of Lagrangian flow with circle symmetry.
New compact examples of pseudo-Kähler manifolds with essential conformal transformations found.
New Poisson manifolds created over 2-tori.
Compact, non-convex curve flows are created.
We present examples, both compact and non-compact complete, of lo- cally non-homogeneous proper A-manifolds.
The aim of this paper is to present the first examples of compact, simply connected holomorphically pseudosymmetric Kahler manifolds.
We construct series of examples of exotic smooth structures on compact locally symmetric spaces of noncompact type. In particular, we obtain higher rank examples, which do not support Riemannian metric of nonpositive curvature. The examples are obtained by taking the connected sum with an exotic sphere. To detect the c…
Paper answers Gromov's compactness question on noncompact manifolds.
The study finds no extremal metrics for eigenvalues on compact manifolds but constructs examples for annuli.
Found a new compact G2-structure on a 7-manifold.
We consider the connected-sum method of constructing compact Riemannian 7-manifolds with holonomy G_2 developed in math.DG/0012189. The method requires pairs of projective complex threefolds endowed with anticanonical K3 divisors, the latter `matching' via a certain non-holomorphic map. Suitable examples of threefolds …
Non-compact flow lines for scalar curvature prescription on manifolds.
The paper classifies structures on complex flag manifolds and provides examples.
We prove that any simply connected compact 3-Sasakian manifold, of dimension seven, is formal if and only if its second Betti number is . In the opposite, we show an example of a 7-dimensional Sasaki-Einstein manifold, with second Betti number , which is formal. Therefore, such an example does not adm…
We present some examples of locally conformal symplectic structures of the first kind on compact nilmanifolds which do not admit Vaisman metrics. One of these examples does not admit locally conformal Kähler metrics and all the structures come from left-invariant locally conformal symplectic structures on the correspon…
New compact Weyl-parallel manifolds discovered in all dimensions n≥5.
We study the existence of three classes of Hermitian metrics on certain types of compact complex manifolds. More precisely, we consider balanced, SKT and astheno-Kähler metrics. We prove that the twistor spaces of compact hyperkähler and negative quaternionic-Kähler manifolds do not admit astheno-Kähler metrics. Then w…
New example shows non-compact manifolds can lack -Calderón-Zygmund inequalities.
This paper characterizes which subsets of C^n can be the set of positions of n points on a linkage in the complex plane C. For example, assuming compactness they are just compact semialgebraic sets. Noncompact configuration spaces are semialgebraics sets invariant under the Euclidean group, with compact quotient.
Classifies complex symplectic structures on Lie algebras with large abelian ideals.
Classifies compact multiplicity free quasi-Hamiltonian manifolds.
Compact quasi-Einstein metrics with constant scalar curvature are locally homogeneous in 3D.
The exceptional holonomy groups are G2 in 7 dimensions, and Spin(7) in 8 dimensions. In a previous paper (Invent. math. 123 (1996), 507-552) the author constructed the first examples of compact 8-manifolds with holonomy Spin(7), by resolving orbifolds T^8/G, where T^8 is the 8-torus and G a finite group of automorphism…
In this paper we introduce a new method for manufacturing harmonic morphisms from semi-Riemannian manifolds. This is employed to yield a variety of new examples from the compact Lie groups SO(n), SU(n) and Sp(n) equipped with their standard Riemannian metrics. We develop a duality principle and show how this can be use…
New -instantons constructed on Joyce's manifold.
Study on prescribing Ricci curvature on compact Lie groups.
We give a new method for manufacturing complete minimal submanifolds of compact Lie groups and their homogeneous quotient spaces. For this we make use of harmonic morphisms and basic representation theory of Lie groups. We then apply our method to construct many examples of compact minimal submanifolds of the special u…
Study on transverse Ricci solitons on compact foliated manifolds.
New hyperbolic manifolds without spin structures found.
We construct a family of compact almost Calabi--Yau manifolds of complex dimension 3 and therein a corresponding family of compact special Lagrangians with one-point singularities modelled upon that T^2-cone constructed by Harvey--Lawson and characterized by Haskins as a stable T^2-cone in the terminology by Joyce.
New examples of rigid Lie foliations with dense leaves found.
We construct examples of exponentially asymptotically cylindrical Riemannian 7-manifolds with holonomy group equal to G_2. To our knowledge, these are the first such examples. We also obtain exponentially asymptotically cylindrical coassociative calibrated submanifolds. Finally, we apply our results to show that one of…
Approximates compact and non-compact Sasakian manifolds in spheres.
We develop a general structure theory for compact homogeneous Riemannian manifolds in relation to the co-index of symmetry. We will then use these results to classify irreducible, simply connected, compact homogeneous Riemannian manifolds whose co-index of symmetry is less or equal than three. We will also construct ma…
New hyperKähler orbifolds of Kummer type discovered.
-monopoles are solutions to gauge theoretical equations on -manifolds. If the -manifolds under consideration are compact, then any irreducible -monopole must have singularities. It is then important to understand which kind of singularities -monopoles can have. We give examples (in the noncompa…