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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.

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48 results for Bourgeois construction

Bourgeois structures are tight in 5D and provide symplectic fillability obstructions.

problem Understanding the tightness and symplectic fillability of Bourgeois contact structures.
method Explicit construction and obstructions for symplectic fillings.
result Bourgeois structures are universally tight in 5D and provide obstructions in higher dimensions.

Given a contact structure on a manifold VV together with a supporting open book decomposition, Bourgeois gave an explicit construction for a contact structure on V×T2V \times \mathbb{T}^2. We prove that all such structures are universally tight in dimension 55, independent on whether the original contact manifold is ti…

2019-03-28abs ↗pdf ↗

We describe a necessary and sufficient condition for a principal circle bundle over an even-dimensional manifold to carry an invariant contact structure. As a corollary it is shown that all circle bundles over a given base manifold carry an invariant contact structure, only provided the trivial bundle does. In particul…

2011-07-25abs ↗pdf ↗

We show that if a manifold M admits a contact structure, then so does M\times S^2. Our proof relies on surgery theory, a theorem of Eliashberg on contact surgery and a theorem of Bourgeois showing that if M admits a contact structure then so does M\times T^2.

2013-05-14abs ↗pdf ↗

We consider invariant symplectic connections \nabla on homogeneous symplectic manifolds (M,ω)(M,ω) with curvature of Ricci type. Such connections are solutions of a variational problem studied by Bourgeois and Cahen, and provide an integrable almost complex structure on the bundle of almost complex structures compatible…

2000-06-28abs ↗pdf ↗

In various situations in Floer theory, one extracts homological invariants from "Morse-Bott" data in which the "critical set" is a union of manifolds, and the moduli spaces of "flow lines" have evaluation maps taking values in the critical set. This requires a mix of analytic arguments (establishing properties of the m…

2017-11-27abs ↗pdf ↗

Article constructs coassociative submanifolds in Joyce's G2G_2-manifolds.

problem Constructing coassociative submanifolds in Joyce's G2G_2-manifolds.
method Using Joyce's generalised Kummer construction, focusing on the critical region where the metric degenerates.
result The volume of the coassociatives shrinks to zero as the orbifold-limit is approached.

The twist construction is a geometric model of T-duality that includes constructions of nilmanifolds from tori. This paper shows how one-dimensional foliations on manifolds may be used in a shear construction, which in algebraic form builds certain solvable Lie groups from Abelian ones. We discuss other examples of geo…

2015-05-31abs ↗pdf ↗

We describe various constructions in Sasakian geometry. First we generalize the join construction of the first two authors to arbitrary Sasakian manifolds. We then give several examples, including ones which prove the existence of Sasakian-Einstein metrics on manifolds homeomorphic to S2×S5.S^2\times S^5. Then we use a gen…

2006-02-10abs ↗pdf ↗

The paper constructs infinitely many surfaces with specific mean curvature.

problem Creating surfaces with prescribed mean curvature in the presence of a strictly stable minimal surface.
method Synthesizing ideas from previous constructions to create multiple surfaces.
result Infinitely many distinct surfaces with prescribed mean curvature are constructed.

We construct bi-invariant total orderings of residually torsion-free nilpotent groups by using Chen's iterated integrals. This construction can be seen as a generalization of the Magnus ordering of the free groups, and equivalent to the classical construction which uses an iteration of central extensions. Our geometric…

2010-05-21abs ↗pdf ↗

We introduce the cutting construction of possibly non-compact symplectic toric manifolds, in particular, toric symplectic cones that correspond to a weakly convex good cone. Since the symplectization of a toric contact manifold is a toric symplectic cone, we can also construct toric contact manifolds that correspond to…

2013-01-13abs ↗pdf ↗

We construct calibrated submanifolds of R^7 and R^8 by viewing them as total spaces of vector bundles and taking appropriate sub-bundles which are naturally defined using certain surfaces in R^4. We construct examples of associative and coassociative submanifolds of R^7 and of Cayley submanifolds of R^8. This construct…

2004-07-31abs ↗pdf ↗

The paper constructs solutions to a critical Dirac equation on spheres.

problem Solving the critical Dirac equation on spheres with singularities.
method Constructing Delaunay-type solutions and another kind of singular solutions.
result The constructed solutions are building blocks for singular solutions on Spin manifolds.

In this paper, we construct the index bundle gerbe of a family of self-adjoint Dirac-type operators, refining a construction of Segal. In a special case, we construct a geometric bundle gerbe called the caloron bundle gerbe, which comes with a natural connection and curving, and show that it is isomorphic to the analyt…

2011-07-19abs ↗pdf ↗

New explicit constructions of unbalanced Ramanujan bipartite graphs.

problem Constructing bipartite Ramanujan graphs with specified degrees and avoiding certain edges.
method Presented explicit constructions and discussed known methods for Ramanujan graph construction.
result Affirmative answer to constructing unbalanced Ramanujan bipartite graphs under certain conditions.

Springer varieties appear in both geometric representation theory and knot theory. Motivated by knot theory and categorification Khovanov provides a topological construction of (n/2,n/2)(n/2, n/2) Springer varieties. We extend Khovanov's construction to all two-row Springer varieties. Using the combinatorial and diagrammatic …

2010-07-05abs ↗pdf ↗

This is the second paper in a series of papers aimed at providing a geometric construction of modular functors and topological quantum field theories from conformal field theory building on the constructions in [TUY] and [KNTY]. We give a geometric construct of a modular functor for any simple Lie-algebra and any level…

2003-06-16abs ↗pdf ↗

We give an algebro-geometric construction of some of the non-arithmetic ball quotients constructed by the author, Parker and Paupert. The new construction reveals a relationship between the corresponding orbifold fundamental groups and the automorphism group of the Klein quartic, and also with groups constructed by Bar…

2016-05-12abs ↗pdf ↗

The article consists of the Russian and English variants of Ph.D. Thesis in which the answers is given on the following questions: 1. how to construct the spinor formalism for n=6; 2. how to construct the spinor formalism for n=8; 3. how to prolong the Riemannian connection from the tangent bundle into the spinor one w…

2012-04-01abs ↗pdf ↗

Constructs Lepage equivalents for arbitrary-order Lagrangians.

problem Creating Lepage equivalents for complex Lagrangians.
method Uses variational bicomplex and symmetric linear connections to construct Lepage equivalents satisfying the closure property.
result Shows how to extend global Lepage equivalents to ones satisfying the closure property.

We give a general procedure for gluing together possibly noncompact manifolds of constant scalar curvature which satisfy an extra nondegeneracy hypothesis. Our aim is to provide a simple paradigm for making `analytic' connected sums. In particular, we can easily construct complete metrics of constant positive scalar cu…

1995-12-01abs ↗pdf ↗

The paper studies pseudo-Anosov maps from typical Thurston constructions.

problem Estimating the entropy of pseudo-Anosov maps from Thurston's constructions.
method Developed a method to extract information about random walks associated with Thurston's construction.
result Random walks eventually become pseudo-Anosov under certain conditions.