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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.

169,291 papers · 148 categories

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25.0%50.0%75.0%100.0% · May 199319922001200920182026
48 results for spin-c manifolds

In this paper, we extend the study of generalized Killing spinors on Riemannian Spinc^c manifolds started by Moroianu and Herzlich to complex Killing functions. We prove that such spinor fields are always real Spinc^c Killing spinors or imaginary generalized Spinc^c Killing spinors, providing that the dimension of t…

2013-11-05abs ↗pdf ↗

Classifies manifolds with specific spinors and constructs parallel spinors.

problem Classifying manifolds with generalized Killing spinors.
method Explicitly constructs parallel spinors and considers modified Dirac currents.
result Classifies Riemannian spin^c manifolds with type I and II imaginary generalized Killing spinors.

Totally umbilical hypersurfaces in Spin^c manifolds with special spinors have constant mean curvature.

problem Characterizing totally umbilical hypersurfaces in Spin^c manifolds with specific spinor fields.
method Proving constant mean curvature for hypersurfaces carrying parallel, real or imaginary Killing spinors.
result Results extend to Spin^c case, generalizing O. Kowalski's theorem.

We derive various pinching results for small Dirac eigenvalues using the classification of spinc\text{spin}^c and spin manifolds admitting nontrivial Killing spinors. For this, we introduce a notion of convergence for spinc\text{spin}^c manifolds which involves a general study on convergence of Riemannian manifolds with a pr…

2016-04-06abs ↗pdf ↗

A G-equivariant spin^c structure on a manifold gives rise to a virtual representation of the group G, called the spin^c quantization of the manifold. We present a cutting construction for S^1-equivariant spin^c manifolds, and show that the quantization of the original manifold is isomorphic to the direct sum of the qua…

2007-08-08abs ↗pdf ↗

On SpincSpin^c manifolds, we study the Energy-Momentum tensor associated with a spinor field. First, we give a spinorial Gauss type formula for oriented hypersurfaces of a SpincSpin^c manifold. Using the notion of generalized cylinders, we derive the variationnal formula for the Dirac operator under metric deformation and po…

2010-11-01abs ↗pdf ↗

The paper classifies hypersurfaces in Spinc^c manifolds that satisfy a specific inequality.

problem Classifying hypersurfaces in Spinc^c manifolds that satisfy a particular inequality.
method Using the Spinc^c Bär inequality and properties of real Killing spinors.
result Hypersurfaces satisfying the equality case in the Spinc^c Bär inequality are slices of cones over Riemannian Spinc^c manifolds.

The study finds hyperbolic manifolds without spin^c structures in dimensions 5 and above.

problem Existence of closed hyperbolic manifolds without spin^c structures.
method Proof of existence and commensurability classes for manifolds with non-vanishing third Stiefel-Whitney class.
result Infinitely many commensurability classes of closed hyperbolic manifolds without spin^c structures.

We define spin-c prequantization of a symplectic manifold to be a spin-c structure and a connection which are compatible with the symplectic form. We describe the cutting of an S^1-equivariant spin-c prequantization. The cutting process involves a choice of a spin-c prequantization for the complex plane. We prove that …

2007-10-23abs ↗pdf ↗

We characterize certain CR structures of arbitrary codimension (different from 3, 4 and 5) on Riemannian Spinc^c manifolds by the existence of a Spinc^c structure carrying a strictly partially pure spinor field. Furthermore, we study the geometry of Riemannian Spinc^c manifolds carrying a strictly partially pure spi…

2012-08-09abs ↗pdf ↗

We define a `Higgs field' for a four-dimensional spinc^c-manifold to be a smooth section of its positive half-spinor bundle, transverse to the zero section, and defined only up to a positive functional factor. This is intended to be a generalization of almost complex structures on real four-manifolds, each of which ma…

2002-10-16abs ↗pdf ↗

We show that a homotopy equivalence between manifolds induces a correspondence between their spin^c-structures, even in the presence of 2-torsion. This is proved by generalizing spin^c-structures to Poincare complexes. A procedure is given for explicitly computing the correspondence under reasonable hypotheses.

1997-05-09abs ↗pdf ↗

The Seiberg-Witten equations are lifted to Kaluza-Klein 5-manifolds.

problem Solving the Seiberg-Witten equations on 4-manifolds with circle bundles.
method Lifts spinor and gauge field to a Kaluza-Klein metric, equivalent to solving a Dirac equation.
result Irreducible solutions to Seiberg-Witten equations on 4-manifolds are equivalent to solutions on Kaluza-Klein circle bundles.

The study explores psc-metrics on non-spin manifolds with pin^\pm or spin^c structures.

problem Existence of psc-metrics on non-spin manifolds with specific structures.
method Analysis of Dirac operators and index theory on pin^\pm or spin^c manifolds.
result The index of a Dirac operator controls the existence of psc-metrics on certain manifolds.

It is well known that spinors on oriented Riemannian manifolds cannot be defined as sections of a vector bundle associated with the frame bundle. For this reason spin and spin^c structures are often introduced. In this paper we prove that spin^c structures have a universal property among all other structures that enabl…

2007-09-15abs ↗pdf ↗

Quantum invariant constructed for sutured 3-manifolds using Hopf superalgebra.

problem Quantum invariants for balanced sutured 3-manifolds with SpincSpin^{c} structure.
method Involutive Hopf superalgebra HH and Fox calculus to compute the invariant.
result Invariant is a normalization of Reidemeister torsion when HH is Borel subalgebra of Uq(gl(11))U_{q}(\mathfrak{gl}(1|1)).

Simply connected 3-dimensional homogeneous manifolds E(κ,τ)E(κ, τ), with 4-dimensional isometry group, have a canonical Spinc^c structure carrying parallel or Killing spinors. The restriction to any hypersurface of these parallel or Killing spinors allows to characterize isometric immersions of surfaces into E(κ,τ)E(κ, τ). As…

2012-03-14abs ↗pdf ↗

The study classifies spinc^c manifolds with positive generalized scalar curvature.

problem Classifying spinc^c manifolds with positive generalized scalar curvature.
method Using generalized scalar curvature, index of spinc^c Dirac operator, and surgery techniques.
result Positive generalized scalar curvature metrics exist if and only if a specific invariant vanishes.

This paper gives a combinatorial description of spin and spin^c-structures on triangulated PL-manifolds of arbitrary dimension. These formulations of spin and spin^c-structures are established primarily for the purpose of aiding in computations. The novelty of the approach is we rely heavily on the naturality of binary…

2013-06-20abs ↗pdf ↗

Paradan and Vergne generalised the quantisation commutes with reduction principle of Guillemin and Sternberg from symplectic to Spinc^c-manifolds. We extend their result to noncompact groups and manifolds. This leads to a result for cocompact actions, and a result for non-cocompact actions for reduction at zero. The r…

2014-08-01abs ↗pdf ↗

We present a definition of Riemannian manifold in noncommutative geometry. Using products of unbounded Kasparov modules, we show one can obtain such Riemannian manifolds from noncommutative spin^c manifolds; and conversely, in the presence of a spin^c structure. We also show how to obtain an analogue of Kasparov's fund…

2011-09-10abs ↗pdf ↗

In this paper, we extend the Hijazi type inequality, involving the Energy-Momentum tensor, to the eigenvalues of the Dirac operator on complete Riemannian Spinc^c manifolds without boundary and of finite volume. Under some additional assumptions, using the refined Kato inequality, we prove the Hijazi type inequality f…

2011-01-23abs ↗pdf ↗

This paper explores conditions for positive scalar curvature on spin^c manifolds.

problem Conditions for the existence of metrics with positive scalar curvature on spin^c manifolds.
method Introduces a new scalar-valued function and uses it to study positivity conditions.
result Equivalence between positivity of the new scalar function and the old twisted scalar curvature.

In this paper, we write down Seiberg-Witten equations on contact metric manifolds of dimension 5. Any contact metric manifold has a spin^c structure. For Dirac equation we use Dirac type operators associated to the generalized Tanaka-Webster connection on spin^c spinor bundle of a contact metric manifold. For curvature…

2013-06-05abs ↗pdf ↗

We construct a generalized Witten genus for spinc^c manifolds, which takes values in level 1 modular forms with integral Fourier expansion on a class of spinc^c manifolds called stringc^c manifolds. We also construct a mod 2 analogue of the Witten genus for 8k+28k+2 dimensional spin manifolds. The Landweber-Stong type…

2010-03-11abs ↗pdf ↗

We extend to the eigenvalues of the hypersurface Spinc^c Dirac operator well known lower and upper bounds. Examples of limiting cases are then given. Futhermore, we prove a correspondence between the existence of a Spinc^c Killing spinor on homogeneous 3-dimensional manifolds E(κ,τ)\mathbb E^*(κ, τ) with 4-dimensional is…

2012-07-12abs ↗pdf ↗

Alternative proof and description of orientations for instanton moduli spaces.

problem Describing the relation between different orientations of GG-instanton moduli spaces.
method Using Witten localization of the index of a Dirac type operator.
result Alternative construction and proof of orientability of instanton moduli spaces.