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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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85171256341 · Jun 202019922001200920172026
48 results for Gassner representation

We show how Conway's multivariable potential function can be constructed using braids and the reduced Gassner representation. The resulting formula is a multivariable generalization of a construction, due to Kassel-Turaev, of the Alexander-Conway polynomial in terms of the Burau representation. Apart from providing an …

2017-09-11abs ↗pdf ↗

We study the Gassner representation of the pure braid group PnP_n by considering its restriction to a free subgroup FF. The kernel of the restriction is shown to lie in the subgroup [Γ3F,Γ2F][Γ^3 F,Γ^2 F], sharpening a result of Lipschutz.

2004-03-26abs ↗pdf ↗

The Gassner representation of the pure braid group to GLn(Z[Zn])GL_n(Z[Z^n]) can be extended to give a representation of the concordance group of nn-strand string links to GLn(F)GL_n(F), where FF is the field of quotients of $\zz[\zz^n]$, F=Q(t1,...,tn) F = Q(t_1,...,t_n); this was first observed by Le Dimet. Here we present simple new pers…

1998-06-08abs ↗pdf ↗

Long and Moody gave a method of constructing representations of the braid group B_n. We discuss some ways to generalize their construction. One of these gives representations of subgroups of B_n, including the Gassner representation of the pure braid group as a special case. Another gives representations of the Hecke a…

2008-07-18abs ↗pdf ↗

Ihara initiated to study a certain Galois representation which may be seen as an arithmetic analogue of the Artin representation of a pure braid group. We pursue the analogies in Ihara theory further, following after some issues and their inter-relations in the theory of braids and links such as Milnor invariants, John…

2016-08-29abs ↗pdf ↗

Researchers link knot Floer homology, Burau representation, and quantum gl(1|1).

problem Understanding the Burau representation and its relation to knot Floer homology.
method Developed a Heegaard Floer homology theory and associated a bordered sutured Heegaard Floer homology group to any tangle.
result Established a connection between the Burau representation and quantum gl(1|1), leading to a geometric proof of the braid representation.

We study generalizations of a classical link invariant -- the multivariable Alexander polynomial -- to tangles. The starting point is Archibald's tMVA invariant for virtual tangles which lives in the setting of circuit algebras, and whose target space has dimension that is exponential in the number of strands. Using th…

2016-11-28abs ↗pdf ↗

For a 3-manifold M, McMullen derived from the Alexander polynomial of M a norm on H^1(M, R) called the Alexander norm. He showed that the Thurston norm on H^1(M, R), which measures the complexity of a dual surface, is an upper bound for the Alexander norm. He asked if these two norms were equal on all of H^1(M,R) when …

1999-08-11abs ↗pdf ↗

Extends a formula for the homomorphism defect of a signature map to coloured braids.

problem Evaluate the homomorphism defect of a signature map for coloured braids.
method Uses a 4-dimensional interpretation of the signature and new 4D tools like the Maslov index and isotropic functor.
result Generalizes the formula of Gambaudo and Ghys to coloured braids and tangles.

Ribbon tangles are proper embeddings of tori and cylinders in the 44-ball~B4B^4, "bounding" 33-manifolds with only ribbon disks as singularities. We construct an Alexander invariant A\mathsf{A} of ribbon tangles equipped with a representation of the fundamental group of their exterior in a free abelian group GG. Th…

2016-02-19abs ↗pdf ↗

Proves EGF representations in specific geometric contexts.

problem Understanding representations of groups with hyperbolic properties.
method Analyzes projectively convex cocompact manifolds and convex projective manifolds with generalized cusps.
result Holonomy representations of specific geometric manifolds are EGF representations.

Study k-positive surface group representations and their degenerations.

problem Understanding the behavior of surface group representations under degenerations.
method Introduced k-positive representations and studied their degenerations using a limit theorem for positively ratioed representations.
result Degenerations of k-positive representations can lead to limits that are at least (k-3)-positive and irreducible limits are (k-1)-positive.

Develops theory of Anosov representations for Fuchsian groups, showing stability and analytical properties.

problem Understanding geometrically finite Fuchsian groups and their representations.
method Theory of Anosov representations, type-preserving deformations, limit maps, relative Anosov and dominated representations.
result Cusped Hitchin representations are Borel Anosov, stable under deformations, and limit maps vary analytically.

New representations defined for groups and graphs, with applications to stable representations.

problem Defining and constructing new types of representations for groups and graphs.
method Introducing (R,Λ)(R,Λ)-directed Anosov representations and using Fock-Goncharov positivity to construct them.
result Constructs large families of primitive stable representations from F2F_2 to PGL(V)\mathrm{PGL}(V), including non-discrete and non-faithful examples.

Study subgroup actions on mapping class groups using Heisenberg representations.

problem Untwisting representations of mapping class groups on Heisenberg subgroups.
method Restrict and analyze twisted representations of mapping class groups to Heisenberg subgroups.
result Untwisting representations on Torelli group for any Heisenberg representation.

Researchers describe unitary representations of mixed braid groups.

problem Understanding unitary representations of mixed braid groups.
method Explicitly describe unitary representations on cohomology of Abelian branched covers.
result Image of the representation is generated by complex reflections and related to the multivariate Burau representation.

This paper addresses law invariant coherent risk measures and their Kusuoka representations. By elaborating the existence of a minimal representation we show that every Kusuoka representation can be reduced to its minimal representation. Uniqueness -- in a sense specified in the paper -- of the risk measure's Kusuoka r…

2012-10-26abs ↗pdf ↗

A very popular problem on braid groups has recently been solved by Bigelow and Krammer, namely, they have found a faithful linear representation for the braid group B_n. In their papers, Bigelow and Krammer suggested that their representation is the monodromy representation of a certain fibration. Our goal in this pape…

2001-11-16abs ↗pdf ↗

Let S be a closed orientable surface of genus at least 2 and let G be a semisimple real algebraic group of non-compact type. We consider a class of representations from the fundamental group of S to G called positively ratioed representations. These are Anosov representations with the additional condition that certain …

2016-09-05abs ↗pdf ↗

In this paper, we introduce a study of prolongations of representations of Lie groups. We obtain a faithful (one-to-one) representation of TG where G is a finite-dimensional Lie group and TG is the tangent bundle of G, by using (not necessarily faithful) representations of G. We show that tangent functions of Lie group…

2013-10-08abs ↗pdf ↗

Paper addresses the disparity between sampled and mean representations in disentangled learning.

problem Disparity between sampled and mean representations in disentangled learning.
method Proposes a method to eliminate the disparity by proving and utilizing the relationship between total correlation of sampled and mean representations for multivariate normal distributions.
result Demonstrates that a factorized mean representation can have lower total correlation than the sampled representation.

New findings on cusped Borel Anosov representations and their properties.

problem Characterizing and understanding cusped Borel Anosov representations.
method Analyzing representations of lattices in PGL2(R)PGL_2(\mathbb{R}) to PGLd(R)PGL_d(\mathbb{R}).
result Cusped Borel Anosov representations with specific properties are Hitchin representations.

The paper formalizes criteria for non-spurious and disentangled representations using causal methods.

problem Formalizing criteria for non-spurious and disentangled representations in representation learning.
method Causal perspective, counterfactual quantities, observable consequences of causal assertions.
result Computable metrics for assessing representation learning based on observed data.

Characterizes Anosov reducible representations in terms of eigenvalues.

problem Understanding Anosov representations in reducible settings.
method Characterizes Anosov representations using eigenvalue magnitudes of irreducible block factors.
result Connected components of character varieties do not contain reducible representations for many non-elementary hyperbolic groups.

Convex-cocompact groups in infinite hyperbolic space are deformable.

problem Understanding deformability of convex-cocompact groups in infinite hyperbolic spaces.
method Proving convex-cocompact representations form an open set and using bending to deform them.
result Deformable convex-cocompact representations of surface groups not conjugate to exotic PSL(2,R) representations.

In this article we introduce order preserving representations of fundamental groups of surfaces into Lie groups with bi-invariant orders. By relating order preserving representations to weakly maximal representations, introduced in arXiv:1305.2620, we show that order preserving representations into Lie groups of Hermit…

2016-01-10abs ↗pdf ↗

We introduce and study a new class of representations of surface groups into Lie groups of Hermitian type, called {\em weakly maximal} representations. We prove that weakly maximal representations are discrete and injective and we describe the structure of the Zariski closure of their image. Furthermore we prove that t…

2013-05-12abs ↗pdf ↗

We characterize groups admitting Anosov representations into SL(3,R)\mathsf{SL}(3,\mathbb R), projective Anosov representations into SL(4,R)\mathsf{SL}(4,\mathbb R), and Borel Anosov representations into SL(4,R)\mathsf{SL}(4,\mathbb R). More generally, we obtain bounds on the cohomological dimension of groups admitting PkP_k-Anosov r…

2019-04-03abs ↗pdf ↗

New method finds Fuchsian representations dominating others in surface group representations.

problem Finding Fuchsian representations that dominate others in surface group representations.
method Straightening the pleated plane and applying strip deformations.
result There exists a Fuchsian representation that strictly dominates a given non-Fuchsian representation.

The paper proposes a model to learn disentangled representations using mutual information.

problem Learning disentangled representations from shared and exclusive attributes.
method Mutual information maximization for shared attributes and minimization for disentanglement.
result The proposed model outperforms state-of-the-art models in representation disentanglement.

The paper studies conjugating complex representations into real ones.

problem Understanding representations of surface groups into complex Lie groups.
method Analyzes representations of finitely generated groups into PGL(k,C)PGL(k, \mathbb{C}) and determines conjugacy conditions.
result Identifies representations in the larger variety that are conjugate in PGL(k,C)PGL(k, \mathbb{C}) to a representation in PGL(k,R)PGL(k, \mathbb{R}).

This paper explores the complexity of learning representations in contextual linear bandits.

problem Understanding the complexity of representation learning in contextual linear bandits.
method Systematic approach to representation learning in contextual linear bandits, focusing on instance-dependent perspective.
result Representation learning is fundamentally more complex than linear bandits, with some cases being arbitrarily harder.

In this paper, I introduce weak representations of a Lie groupoid GG. I also show that there is an equivalence of categories between the categories of 2-term representations up to homotopy and weak representations of GG. Furthermore, I show that any VB-groupoid is isomorphic to an action groupoid associated to a weak…

2017-04-17abs ↗pdf ↗