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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.

168,982 papers · 148 categories

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4589134178 · May 202619922001200920172026
48 results for coindex three

The paper studies Einstein metrics on specific manifolds and their rigidity properties.

problem Investigating rigidity of Einstein metrics on homogeneous Gray manifolds.
method Computing coindex and analyzing infinitesimal deformations of Einstein metrics.
result Infinitesimal Einstein deformations on F1,2=SU(3)/T2F_{1,2}=\mathrm{SU}(3)/T^2 are not integrable.

The paper defines a new invariant for links and uses it to show non-sliceness.

problem Determining whether a link is slice or not.
method Defining a new concordance invariant from the Seifert form and using it to bound the slice Euler characteristic.
result The Witt coindex provides an upper bound for the slice Euler characteristic of a link.

Defines coupled embeddability for maps on products of spaces, generating examples and nonexamples.

problem Understanding when maps on products of spaces can be embedded.
method Uses known results for nonsingular biskew and bilinear maps, studies genericity properties, extends Whitney embedding theorems, and relates to Z/2\mathbb{Z}/2-coindex of embedding spaces.
result Generates strong obstructions to coupled embeddability in terms of combinatorics of triangulations.

The paper studies stability of Einstein metrics on non-simple Lie group homogeneous spaces.

problem Classifying compact homogeneous spaces with standard Einstein metrics.
method Analysis of scalar curvature functional and coindex.
result Most standard Einstein metrics on non-simple Lie group homogeneous spaces are unstable.

We study the linear stability of Einstein metrics of Riemannian submersion type. First, we derive a general instability condition for such Einstein metrics and provide some applications. Then we study instability arising from Riemannian product structures on the base. As an application, we estimate the coindex of the E…

2018-08-16abs ↗pdf ↗

Study on stability of non-diagonal Einstein metrics on specific homogeneous spaces.

problem Stability analysis of non-diagonal Einstein metrics on HimesH/ΔKH imes H/ΔK.
method Formula for scalar curvature, study of stability with Hilbert action.
result Non-diagonal Einstein metrics on MM are unstable with different coindexes.

Counterexample disproves Borde-Sorkin conjecture on causal continuity of Morse spacetimes.

problem Disproving the Borde-Sorkin conjecture on causal continuity of Morse spacetimes.
method Provided a counterexample with low regularity causal structure and causal bubbling.
result Borde-Sorkin conjecture does not hold for Morse spacetimes with large anisotropy.

We prove a semi-Riemannian version of the celebrated Morse Index Theorem for geodesics in semi-Riemannian manifolds; we consider the general case of both endpoints variable on two submanifolds. The key role of the theory is played by the notion of the {\em Maslov index} of a semi-Riemannian geodesic, which is a homolog…

2000-11-14abs ↗pdf ↗

We study three-dimensional Alexandrov spaces with a lower curvature bound, focusing on extending three classical results on three-dimensional manifolds: First, we show that a closed three-dimensional Alexandrov space of positive curvature, with at least one topological singularity, must be homeomorphic to the suspensio…

2013-07-15abs ↗pdf ↗

New proof finds three divergence-free vector fields for any 3D manifold.

problem Proving the existence of divergence-free vector fields on 3D manifolds.
method Using geometric properties of eigenspinors in three dimensions.
result Found three divergence-free vector fields that are orthogonal and have the same length at every point.

It is shown that any closed three-manifold M obtained by integral surgery on a knot in the three-sphere can always be constructed from integral surgeries on a 3-component link L with each component being an unknot in the three-sphere. It is also interesting to notice that infinitely many different integral surgeries on…

2008-01-22abs ↗pdf ↗

We construct four-dimensional symplectic cobordisms between contact three-manifolds generalizing an example of Eliashberg. One key feature is that any handlebody decomposition of one of these cobordisms must involve three-handles. The other key feature is that these cobordisms contain chains of symplectically embedded …

2006-06-16abs ↗pdf ↗

The Laplace spectrum uniquely identifies five out of eight metrically maximal three-dimensional geometries.

problem Characterizing compact locally homogeneous three-manifolds using their Laplace spectra.
method Analyzing geometric structures and their spectral properties.
result For five out of eight metrically maximal three-dimensional geometries, compact locally homogeneous three-manifolds are uniquely determined by their spectra.

We prove two rigidity results for complete Riemannian three-manifolds of higher rank. Complete three-manifolds have higher spherical rank if an only if they are spherical space forms. Complete finite volume three-manifolds have higher hyperbolic rank if and only if they are hyperbolic space forms.

2016-08-16abs ↗pdf ↗

We show that a free period three action on a lens space is standard, i.e. the quotient is homeomorphic to a lens space. This is an extension of the result for period three actions on the three-sphere, arXiv:math.GT/0204077, by the author and J. Hyam Rubinstein.

2003-11-02abs ↗pdf ↗

We construct a series of finitely presented semigroups. The centers of these semigroups encode uniquely up to rigid ambient isotopy in 3-space all non-oriented spatial graphs. This encoding is obtained by using three-page embeddings of graphs into the product of the line with the cone on three points. By exploiting thr…

2004-07-19abs ↗pdf ↗

Computes the decomposition of rank-three bundles over the projective line with three marked points.

problem Decomposing rank-three bundles over the projective line with three marked points.
method Using the monodromy derivative to compute the roots of the bundles.
result Computes the exact decomposition of rank-three bundles for m=3m = 3.

Motivated by classical theorems on minimal surface theory in compact hyperbolic three-manifolds, we investigate the questions of existence and deformations for least area minimal surfaces in complete noncompact hyperbolic three-manifold of finite volume. We prove any closed immersed incompressible surface can be deform…

2015-07-17abs ↗pdf ↗

Study finds index of symmetry for solvable 3D Lie groups with left-invariant metrics.

problem Determining the index of symmetry for solvable 3D Lie groups with left-invariant metrics.
method Examined all solvable three-dimensional Lie groups, combined with previous work on unimodular groups.
result Index of symmetry is positive for every solvable 3D Lie algebra with a left-invariant metric, and is never 2.

The paper proves three circles theorems and Liouville type theorems for subharmonic and holomorphic functions.

problem Establishing theorems for subharmonic and holomorphic functions on specific geometric structures.
method Using subharmonic and holomorphic functions on Riemannian manifolds and gradient shrinking Ricci solitons.
result Proves Liouville type theorems as applications of the established theorems.

Constructs a family of genus three minimal surfaces with parallel ends.

problem Creating embedded doubly periodic minimal surfaces with specific topological properties.
method Constructs a one-parameter family of surfaces with given Weierstrass data and solves the period problem.
result Solves the two dimensional period problem for the constructed surfaces.

The paper explores actions on metric spaces similar to 3D manifolds, proving rigidity results.

problem Rigidity of actions on metric spaces similar to 3D manifolds.
method Reexamined isometry groups of geometric 3-manifolds, considered homomorphisms to them, established a dichotomy.
result Established a dichotomy between finite image or infinite volume of quotient spaces.

We discuss the existence of the angle between two curves in Teichmüller spaces and show that, in any infinite dimensional Teichmüller space, there exist infinitely many geodesic triangles each of which has the same three vertices and satisfies the property that its three sides have the same and arbitrarily given length…

2013-05-03abs ↗pdf ↗

We show that the equivalence problem for three-dimensional Lorentzian manifolds requires at most the fifth covariant derivative of the curvature tensor. We prove that this bound is sharp by exhibiting a class of 3D Lorentzian manifolds which realize this bound. The analysis is based on a three-dimensional analogue of t…

2012-10-25abs ↗pdf ↗

We determine which three-manifolds are dominated by products. The result is that a closed, oriented, connected three-manifold is dominated by a product if and only if it is finitely covered either by a product or by a connected sum of copies of the product of the two-sphere and the circle. This characterization can als…

2012-02-28abs ↗pdf ↗

The paper characterizes stable cohomotopy groups in codimensions two and three, linking algebraic and geometric perspectives.

problem Characterizing stable cohomotopy groups in specific codimensions.
method Algebraic and geometric approaches, including CW complexes and bordism theory.
result Complete characterizations of stable cohomotopy in codimension two and partial results in codimension three.

Study left invariant Lorentzian metrics on 3D non-unimodular Lie groups.

problem Classify and analyze left invariant Lorentzian metrics on 3D non-unimodular Lie groups.
method Classify metrics up to automorphism, study curvature functions.
result Obtain Ricci operator, scalar curvature, and sectional curvatures as functions of metrics.

In this article, we find the complete list of all contact structures (up to isotopy) on closed three-manifolds which are supported by an open book decomposition having planar pages with three (but not less) boundary components. We distinguish them by computing their first Chern classes and three dimensional invariants …

2007-11-12abs ↗pdf ↗

The paper proves the existence of at least 4 embedded minimal tori in a three-sphere with positive Ricci curvature.

problem Proving the existence of embedded minimal tori in three-spheres with positive Ricci curvature.
method The proof relies on a multiplicity one theorem for the Simon-Smith min-max theory.
result There exist at least 4 distinct embedded minimal tori in the three-sphere with positive Ricci curvature.