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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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48 results for Nil_3

Classifies Nil 3-manifolds as cross-sections of complex hyperbolic surfaces.

problem Identifying Nil 3-manifolds as cross-sections of complex hyperbolic surfaces.
method Comprehensive classification of commensurability classes of cusped, arithmetic, and non-arithmetic complex hyperbolic 2-manifolds.
result Some Nil 3-manifolds are cross-sections in every commensurability class, while others are cross-sections in only one.

The paper studies deformations of Kundt metrics using nil-Killing vector fields.

problem Deformations of Kundt metrics in the direction of type III tensors.
method Characterizations within the Kundt class using nil-Killing vector fields.
result Theorem classifying algebraic stability of tensors and sufficient criteria for preserving spi's.

We prove that the Waldhausen Nil-group associated to a virtually cyclic groups that surjects onto the infinite dihedral group vanishes if and only if the corresponding Farrell Nil-group associated to the canonical index two subgroup is trivial. The proof uses the transfer map to establish one direction, and uses contro…

2006-09-25abs ↗pdf ↗

The study examines closed manifolds with ray nil-affine structures and their completeness.

problem Characterizing closed manifolds with ray nil-affine structures.
method Analyzing properties of nilpotent spaces and flag manifolds, applying rank conditions and automorphism group actions.
result Closed manifolds are either complete or their developing map is a cover onto the complement of a nil-affine subspace.

We study Farrell Nil-groups associated to a finite order automorphism of a ring RR. We show that any such Farrell Nil-group is either trivial, or infinitely generated (as an abelian group). Building on this first result, we then show that any finite group that occurs in such a Farrell Nil-group occurs with infinite mu…

2014-03-27abs ↗pdf ↗

Study of minimal surfaces with non-trivial topology in Heisenberg group using loop group method.

problem Constructing and classifying minimal surfaces with non-trivial topology in the Heisenberg group.
method Generalized Weierstrass type representation and loop group method.
result Classification of equivariant minimal surfaces given by one-parameter subgroups.

In this paper, we study biharmonic maps into Sol and Nil spaces, two model spaces of Thurston's 3-dimensional geometries. We characterize non-geodesic biharmonic curves in Sol space and prove that there exists no non-geodesic biharmonic helix in Sol space. We also show that a linear map from a Euclidean space into Sol …

2006-12-13abs ↗pdf ↗

The paper estimates heights of constant mean curvature graphs in specific spaces.

problem Estimating heights of constant mean curvature graphs in Nil3\mathrm{Nil}_3 and PSL~2(R)\widetilde{PSL}_2(\mathbb{R}).
method Height estimates for compact, constant mean curvature graphs in Nil3\mathrm{Nil}_3 and PSL~2(R)\widetilde{PSL}_2(\mathbb{R}).
result Announced a structure-type result for proper graphs defined on relatively compact domains.

The Farrell-Jones Conjecture holds for groups acting acylindrically on trees.

problem Verifying the Farrell-Jones Conjecture for groups acting on trees.
method Analyzing acylindrical actions on simplicial trees and using the Farrell-Jones Conjecture.
result The Farrell-Jones Conjecture holds for groups acting acylindrically on trees.

We prove some half-space theorems for minimal surfaces in the Heisenberg group Nil_3 and the Lie group Sol_3 endowed with their left-invariant Riemannian metrics. If S is a properly immersed minimal surface in Nil_3 that lies on one side of some entire minimal graph G, then S is the image of G by a vertical translation…

2010-05-21abs ↗pdf ↗

We prove that there are exactly 66 Nil Seifert fibred spaces which can be obtained by Dehn surgeries on non-trefoil knots in S3S^3, with {60,144,156,288,300}\{60, 144, 156, 288, 300\} as the exact set of all such surgery slopes up to taking the mirror images of the knots. We conjecture that there are exactly 44 specific hyperbolic kno…

2014-07-02abs ↗pdf ↗

Study on I\mathcal{I}-preserving diffeomorphisms in Lorentzian manifolds.

problem Existence and properties of I\mathcal{I}-preserving diffeomorphisms in Lorentzian manifolds.
method Analysis of Lie derivatives and nil-Killing vector fields to determine I\mathcal{I}-preserving diffeomorphisms.
result Finite transitive Lie algebra of nil-Killing vector fields exists for Kundt spacetimes with constant scalar polynomial curvature invariants.

Minimal surfaces in Heisenberg group solved via Dirichlet problems.

problem Existence of minimal surfaces in Heisenberg group with balanced metric.
method Solving Dirichlet problems for minimal surface equation.
result Existence of complete properly embedded minimal surfaces.

The paper classifies homogeneous hypersurfaces in three 4D Thurston geometries.

problem Classifying homogeneous hypersurfaces in specific 4D geometries.
method Analyzing isometry groups and applying classification techniques.
result Homogeneous hypersurfaces identified in Sol14\mathrm{Sol}_1^4, Solm,n4\mathrm{Sol}_{m,n}^4 and Nil4\mathrm{Nil}^4.

We study properly discontinuous and cocompact actions of a discrete subgroup ΓΓ of an algebraic group GG on a contractible algebraic manifold XX. We suppose that this action comes from an algebraic action of GG on XX such that a maximal reductive subgroup of GG fixes a point. When the real rank of any simple subg…

2010-07-16abs ↗pdf ↗

This paper shows how post-Lie algebra structures can be induced by simply transitive NIL-affine actions.

problem Understanding which solvable Lie groups can act simply transitively on nilpotent Lie groups.
method Introducing post-Lie algebra structures and showing their correspondence with simply transitive actions.
result Simply transitive NIL-affine actions induce complete post-Lie algebra structures in the 2-step nilpotent case.

Let O be a three-dimensional Nil-orbifold, with branching locus a knot Sigma transverse to the Seifert fibration. We prove that O is the limit of hyperbolic cone manifolds with cone angle in (pi-epsilon, pi). We also study the space of Dehn filling parameters of O-Sigma. Surprisingly it is not diffeomorphic to the defo…

2002-12-20abs ↗pdf ↗

We construct complete, finite volume, 4-dimensional manifolds with sectional curvature 1<K<0-1<K<0 with cusp cross sections compact solvmanifolds.

2012-07-06abs ↗pdf ↗

The paper classifies 3D contact partially hyperbolic diffeomorphisms.

problem Classifying contact partially hyperbolic diffeomorphisms in 3D.
method Smooth classification, conjugation to known flows or automorphisms, use of invariant distributions.
result Classification up to finite quotient or power, conjugation to known structures.

Study algebraic K-theory of 3-manifold groups using Farrell-Jones isomorphism and geometrization.

problem Algebraic K-theory of 3-manifold groups.
method Farrell-Jones isomorphism conjecture, models for virtually cyclic subgroups, geometrization theorem.
result Descriptions of Whitehead groups and algebraic K-theory groups in terms of finite subgroups and Nil-groups.

The paper classifies surfaces in the Heisenberg space invariant under specific isometries.

problem Classifying surfaces in the Heisenberg space with specific geometric properties.
method Analyzing surfaces with mean curvature H=N,zangle+λH=\langle N,\partial_z angle+λ under left-translations, rotations, and helicoidal motions.
result Classification of λλ-translators invariant under specific isometries.

We study the minimal surface equation in the Heisenberg space, Nil_3. A geometric proof of non existence of minimal graphs over non convex, bounded and unbounded domains is achieved (our proof holds in the Euclidean space as well). We solve the Dirichlet problem for the minimal surface equation over bounded and unbound…

2015-08-07abs ↗pdf ↗

For graphs with 13 or more vertices, either the graph or its complement is intrinsically linked.

problem Identifying graphs with 13 or more vertices that are intrinsically linked or their complements.
method Analyzing properties of graphs and their complements to determine if either is intrinsically linked.
result For graphs with 13 or more vertices, either the graph or its complement is intrinsically linked.

In this paper, we give complete classifications of linear \infty-harmonic maps between Euclidean and Heisenberg spaces, between Nil and Sol spaces. We also classify all \infty-harmonic linear endomorphisms of Sol space and show that there is a subgroup of \infty-harmonic linear automorphisms in the group of linea…

2007-11-05abs ↗pdf ↗

We derive the Weierstrass (or spinor) representation for surfaces in three-dimensional Lie groups Nil, \tilde{SL}_2, and Sol with Thurston's geometries and establish the generating equations for minimal surfaces in these groups. By using the spectral properties of the corresponding Dirac operators we find analogs of th…

2005-03-30abs ↗pdf ↗

We study 33-dimensional Ricci solitons which project via a semi-conformal mapping to a surface. We reformulate the equations in terms of parameters of the map; this enables us to give an ansatz for constructing solitons in terms of data on the surface. A complete description of the soliton structures on all the 33-di…

2005-10-14abs ↗pdf ↗

Let N be a simply connected, connected real nilpotent Lie group of finite dimension n. We study subgroups ΓΓ in $\Aff (N)=N\rtimes \Aut (N)$ acting properly discontinuously and cocompactly on N. This situation is a natural generalization of the so-called affine crystallographic groups. We prove that for all dimensions…

2004-09-24abs ↗pdf ↗