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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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25.0%50.0%75.0%100.0% · Sep 199219922001200920172026
48 results for Shi-Tam construction

Motivated by the quasi-local mass problem in general relativity, we apply the asymptotically flat extensions, constructed by Shi and Tam in the proof of the positivity of the Brown--York mass, to study a fill-in problem of realizing geometric data on a 2-sphere as the boundary of a compact 3-manifold of nonnegative sca…

2013-04-02abs ↗pdf ↗

The Positive Mass Theorem for special singular initial data.

problem Proving the positive mass theorem for data with a codimension one singularity.
method Using asymptotically flat spin initial data sets with matching Bartnik data condition involving spacetime rotations.
result Established a spacetime positive mass theorem and rigidity statement.

Suppose that Σ=MΣ=\partial M is the nn-dimensional boundary of a connected compact Riemannian spin manifold (M,  ,  )( M,\langle\;,\;\rangle) with non-negative scalar curvature, and that the (inward) mean curvature HH of ΣΣ is positive. We show that the first eigenvalue of the Dirac operator of the boundary corresponding to…

2015-02-17abs ↗pdf ↗

Consider a triple of "Bartnik data" (Σ,γ,H)(Σ, γ,H), where ΣΣ is a topological 2-sphere with Riemannian metric γγ and positive function HH. We view Bartnik data as a boundary condition for the problem of finding a compact Riemannian 3-manifold (Ω,g)(Ω,g) of nonnegative scalar curvature whose boundary is isometric to (Σ,γ)(Σ,γ)

2011-06-21abs ↗pdf ↗

Compact proof for Brown-York mass positivity and rigidity in flat and spherical spaces.

problem Positivity of Brown-York mass and rigidity of manifolds with mean-convex boundaries.
method Spinorial proof and optimal lower bound for eigenvalues.
result Optimal lower bound for first non-null eigenvalue of Dirac operator.

Study bounds total mean curvature of fill-ins with scalar curvature constraints.

problem Bounding total mean curvature of fill-ins with scalar curvature constraints.
method Combines techniques from Shi-Tam, Shi-Wang-Wei, and recent work on systolic inequality.
result Sharp constant for total mean curvature estimate when boundary metric is flat.

The paper proves a spacetime positive mass theorem for singular initial data sets.

problem Proving the positive mass theorem for initial data sets with corners.
method Extending Hirsch-Kazaras-Khuri's method to singular cases using Hirsch-Miao-Tsang ideas.
result Integral lower bound on spacetime mass and characterisation of zero mass.

Positive mass theorem for tori with scalar curvature bounds.

problem Proving positivity of static quasi-local mass for tori.
method Generalization of Shi-Tam result to 2-tori with specific curvature and scalar curvature bounds.
result Total weighted mean curvature of 2-tori is not greater than that of an isometric embedding into the Kottler manifold.

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 ↗