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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.

168,742 papers · 148 categories

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18365371 · Jun 202619922001200920172026
48 results for nilpotent fibre bundles

The paper disproves a generalized toral rank conjecture with various counter-examples.

problem The conjecture that the sum of Betti numbers of a compact manifold with a torus action is bounded by 2r2^r.
method Provided counter-examples of smooth nilpotent fibre bundles of nilmanifolds with torus fibres of rank rr.
result There are sequences of torus fibrations with total space cohomology dimensions converging to 0 as rank rr increases.

We define the pull-back of a smooth principal fibre bundle, and show that it has a natural principal fibre bundle structure. Next, we analyse the relationship between pull-backs by homotopy equivalent maps. The main result of this article is to show that for a principal fibre bundle over a paracompact manifold, there i…

2001-05-19abs ↗pdf ↗

In a fibre bundle, natural derivatives of a section are defined as tangent vector fields on the image of a section of the fibre bundle. A local extension to vector fields in the tangent bundle leads to a direct proof of the formula expressing the curvature of a connection in terms of covariant derivatives. The result i…

2011-07-08abs ↗pdf ↗

Describes spectral data for singular fibres of a specific Hitchin system.

problem Characterizing singular fibres of the SL(2,C)\mathsf{SL}(2,\mathbb{C})-Hitchin system.
method Using Hecke transformations and analysis of parameter spaces, the paper stratifies and compactifies the singular spaces.
result Large classes of singular fibres are shown to be fibre bundles over Prym varieties.

We put together some of the efforts by several people of making aspects of fibre bundle theory into algebra. The initiator of these efforts was Charles Ehresmann, who put the notion of groupoid and groupoid action in the focus of fibre bundle theory in general, and in connection theory in particular.

2000-05-12abs ↗pdf ↗

The article describes canonical metrics on holomorphic fibre bundles.

problem Existence of canonical metrics on isotrivial Kähler fibrations.
method Induced from Hermite--Einstein connections on holomorphic principal bundles.
result Existence of optimal symplectic connections when principal bundles are polystable.

Study rigidity of Ricci flow limits on nilpotent bundles with zero curvature.

problem Rigidity of invariant Ricci flow blowdown limits on nilpotent bundles with zero curvature.
method Construct a new functional to derive rigidity results for invariant Ricci flow blowdown limits on nilpotent principal bundles with zero associated curvature.
result Proves blowdown limit is locally an expanding Ricci soliton for three-dimensional Heisenberg group structure group.

A stratified bundle is a fibered space in which strata are classical bundles and in which attachment of strata is controlled by a structure category of fibers. Well known results on fibre bundles are shown to be true for stratified bundles; namely the pull back theorem, the bundle theorem and the principal bundle theor…

2002-08-23abs ↗pdf ↗

The paper studies nilpotent structures in oriented neutral vector bundles and neutral hyperKähler structures.

problem Nilpotent structures in oriented neutral vector bundles and their relation to neutral hyperKähler structures.
method Defined HH-nilpotent structures for Lie subgroups of SO(2n,2n)SO(2n, 2n) related to neutral hyperKähler structures.
result Existence of complex and paracomplex structures forming neutral hyperKähler structures if and only if there exists an HH-nilpotent structure.

We consider Schrödinger operators H=Δgε+VH=-Δ_{g_\varepsilon} + V on a fibre bundle MπBM\stackrelπ{\to}B with compact fibres and a metric gεg_\varepsilon that blows up directions perpendicular to the fibres by a factor ε11{\varepsilon^{-1}\gg 1}. We show that for an eigenvalue λλ of the fibre-wise part of HH, satisfying a l…

2014-02-03abs ↗pdf ↗

In classical field theory, the composite fibred manifolds Y -> Z -> X provides the adequate mathematical formulation of gauge models with broken symmetries, e.g., the gauge gravitation theory. This work is devoted to connections on composite fibred manifolds. In particular, we get the horizontal splitting of the vertic…

1994-12-17abs ↗pdf ↗

Parallel transport of a connection in a smooth fibre bundle yields a functor from the path groupoid of the base manifold into a category that describes the fibres of the bundle. We characterize functors obtained like this by two notions we introduce: local trivializations and smooth descent data. This provides a way to…

2007-05-03abs ↗pdf ↗

The study preserves positive Ricci curvature on connected sums of fibre bundles.

problem Preserving positive Ricci curvature on connected sums of fibre bundles.
method Lifting core metrics along general fibre bundles and applying to specific spaces.
result All classes in the torsion-free oriented bordism ring can be represented by connected manifolds of positive Ricci curvature.

Study shows unique harmonic metrics for certain Higgs bundles over non-compact surfaces.

problem Finding harmonic metrics for specific Higgs bundles.
method Generalized Kalka-Yang's theorem for non-compact hyperbolic surfaces to a coupled system.
result Generically regular nilpotent Higgs bundles admit unique maximal harmonic metrics.

We introduce the fibred toric varieties as equivariant CPr\mathbb{C}P^r bundles over lower dimensional toric varieties. An equivalent characterization is that the natural morphisms on them degenerate to bundle projections in the context of variation of toric varieties as GIT quotients. Our main observation is that these…

2010-12-11abs ↗pdf ↗

In this paper, we investigate the behaviour of the Serre spectral sequence with respect to the algebraic structures of string topology in generalized homology theories, specificially with the Chas-Sullivan product and the corresponding coproduct and module structures. We prove compatibility for two kinds of fibre bundl…

2010-01-27abs ↗pdf ↗

In this paper we introduce a generalisation of the notion of holonomy for connections over a bundle map on a principal fibre bundle. We prove that, as in the standard theory on principal connections, the holonomy groups are Lie subgroups of the structure group of the principle fibre bundle and we also derive a straight…

2002-10-02abs ↗pdf ↗

Study families of flat connections with nilpotent Higgs fields, showing similar monodromy to regular Higgs bundles.

problem Investigate Cimes\mathbb{C}^ imes-families of flat connections with nilpotent Higgs fields.
method Analyze families of flat connections including real twistor lines and conformal limits, deducing monodromy similarities.
result Traces of holonomies are asymptotically exponential in rational powers of the parameter of the family.

Let (P,Y)(P, Y) be a bundle gerbe over a fibre bundle YMY \to M. We show that if MM is simply-connected and the fibres of YMY \to M are connected and finite-dimensional then the Dixmier-Douady class of (P,Y)(P, Y) is torsion. This corrects and extends an earlier result of the first author.

2010-07-28abs ↗pdf ↗

We study the behaviour of Laplace-type operators H on a complex vector bundle E \rightarrow M in the adiabatic limit of the base space. This space is a fibre bundle M \rightarrow B with compact fibres and the limit corresponds to blowing up directions perpendicular to the fibres by a factor 1/εε. Under a gap condi…

2017-05-27abs ↗pdf ↗

We compare the higher analytic torsion of Bismut and Lott of a fibre bundle p: M -> B equipped with a flat vector bundle F -> M and a fibre-wise Morse function h on M with a higher torsion T that is constructed in terms of a families Thom-Smale complex associated to h and F, thereby extending previous joint work with B…

2001-11-20abs ↗pdf ↗

The purpose of this note is to present a short elementary proof of a theorem due to Faltings and Laumon, saying that the global nilpotent cone is a Lagrangian substack in the cotangent bundle of the moduli space of G-bundles on a complex compact curve. This result plays a crucial role in the Geometric Langlands program…

1997-04-10abs ↗pdf ↗

This work has the purpose of applying the concept of Geometric Calculus (Clifford Algebras) to the Fibre Bundle description of Quantum Mechanics. Thus, it is intended to generalize that formulation to curved spacetimes [the base space of the fibre bundle in question] in a more natural way. It starts off with a review o…

2003-08-04abs ↗pdf ↗

Constructs covariant derivatives for Ehresmann connections.

problem Developing a method for covariant derivatives in fibre bundles.
method Introducing a vertical endomorphism to construct covariant derivatives on vertical and horizontal distributions.
result Covariant derivatives can be constructed separately on vertical and horizontal distributions and then glued together.

Generalized are the investigated in other works of the author transports along paths in fibre bundles to transports along arbitrary maps in them. Their structure and some properties are studied. Special attention is paid to the linear case and the case when the map's domain is a Cartesian product of two sets. Also cons…

1997-09-20abs ↗pdf ↗

Tautological classes, or generalised Miller-Morita-Mumford classes, are basic characteristic classes of smooth fibre bundles, and have recently been used to describe the rational cohomology of classifying spaces of diffeomorphism groups for several types of manifolds. We show that rationally tautological classes depend…

2017-05-17abs ↗pdf ↗

We slightly extend the notion of a natural fibre bundle by requiring diffeomorphisms of the base to lift to automorphisms of the bundle only infinitesimally, i.e. at the level of the Lie algebra of vector fields. Spin structures are natural only in this extended sense. We classify fibre bundles with this property, assu…

2009-11-18abs ↗pdf ↗

Defines and parametrizes sl(2)\mathfrak{sl}(2)-type singular fibres in symplectic and odd orthogonal Hitchin systems.

problem Characterizing and understanding singular fibres in Hitchin systems.
method Stratification by semi-abelian spectral data, study of irreducible components, global description of degenerations.
result Extension of Langlands duality to sl(2)\mathfrak{sl}(2)-type Hitchin fibres.

New method constructs degenerate Sasakian manifolds from hyperkähler bundles.

problem Constructing degenerate 33-(α,δ)(α,δ)-Sasakian manifolds.
method Using fiber products of Boothby-Wang bundles over hyperkähler manifolds.
result No non-trivial compact examples exist, and one family of nilpotent Lie groups with this geometry is identified.