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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 weak chord index

In this paper we study the chord index of virtual knots, which can be thought of as an extension of the chord parity. We show how to use the chord index to define finite type invariants of virtual knots. The notions of indexed Jones polynomial and indexed quandle are introduced, which generalize the classical Jones pol…

2016-06-05abs ↗pdf ↗

New index principle shows indistinguishability of certain knot crossings.

problem Identifying indistinguishable crossings in knot diagrams.
method Developed a universal index function on knot diagrams that respects Reidemeister moves and sign of crossings.
result Crossings of the same sign in a classical knot diagram cannot be distinguished by any inherent property.

A weak chord index IndInd' is constructed for self crossing points of virtual links. Then a new writhe polynomial WW of virtual links is defined by using IndInd'. WW is a generalization of writhe polynomial defined in [6]. Based on WW, three invariants of virtual links are constructed. These invariants can be used to …

2018-12-13abs ↗pdf ↗

The paper defines new homotopy relations on knot projections and classifies certain knot types.

problem Defining and classifying knot homotopy relations.
method Introducing cross chord numbers and using them to define strong and weak (1, 3) homotopies.
result Complete classification of knot projections with trivializing number two.

The notion of a braided chord diagram is introduced and studied. An equivalence relation is given which identifies all braidings of a fixed chord diagram. It is shown that finite-type invariants are stratified by braid index for knots which can be represented as closed 3-braids. Partial results are obtained about spann…

1998-04-03abs ↗pdf ↗

The paper defines functions from spherical curves and chord diagrams, proving invariance under specific Reidemeister moves.

problem Defining and proving invariance of functions derived from spherical curves and chord diagrams.
method Introducing iαixi\sum_i α_i x_i and iαiildexi\sum_i α_i ilde{x}_i functions, and defining relators of Type (I) ((SII), (WII), (SIII), or (WIII), resp.).
result If iαiildexi\sum_i α_i ilde{x}_i vanishes for the relators of Type (I) ((SII), (WII), (SIII), or (WIII), resp.), then iαixi\sum_i α_i x_i is invariant under specific Reidemeister moves.

In this paper we discuss how to define a chord index via smoothing a real crossing point of a virtual knot diagram. Several polynomial invariants of virtual knots and links can be recovered from this general construction. We also explain how to extend this construction from virtual knots to flat virtual knots.

2018-11-22abs ↗pdf ↗

In this paper we prove an extrinsic one-sided curvature estimate for disks embedded in R3\mathbb{R}^3 with constant mean curvature which is independent of the value of the constant mean curvature. We apply this extrinsic one-sided curvature estimate in [24] to prove to prove a weak chord arc type result for these disks…

2014-08-22abs ↗pdf ↗

Stability of Yang-Mills connections' Morse indices and nullity in 4D.

problem Stability of Yang-Mills connections' Morse indices and nullity in 4D under weak convergence.
method Proves stability results of the Morse index plus nullity of Yang-Mills connections in dimension 4 under weak convergence.
result Stability of the sum of Morse indices and nullity of a sequence of Yang-Mills connections.

We recall the Chernoff-Marsden definition of weak symplectic structure and give a rigorous treatment of the functional analysis and geometry of weak symplectic Banach spaces. We define the Maslov index of a continuous path of Fredholm pairs of Lagrangian subspaces in continuously varying Banach spaces. We derive basic …

2013-01-30abs ↗pdf ↗

Paper explores relationships between triple chords and a specific homotopy relation in knot theory.

problem Understanding the relationship between triple chords and a homotopy equivalence class in knot theory.
method Analyzes the number of triple chords and their connection to the strong (1, 2) homotopy equivalence class.
result Prime knot projections are trivialized by strong (1, 2) homotopy if they have no triple chords.

A chord diagram consists of a circle, called the backbone, with line segments, called chords, whose endpoints are attached to distinct points on the circle. The genus of a chord diagram is the genus of the orientable surface obtained by thickening the backbone to an annulus and attaching bands to the inner boundary cir…

2014-10-22abs ↗pdf ↗

We consider framed chord diagrams, i.e. chord diagrams with chords of two types. It is well known that chord diagrams modulo 4T-relations admit Hopf algebra structure, where the multiplication is given by any connected sum with respect to the orientation. But in the case of framed chord diagrams a natural way to define…

2015-06-30abs ↗pdf ↗

The paper finds at least N orthogonal Finsler geodesic chords in a disk-like manifold.

problem Existence and multiplicity of orthogonal Finsler geodesic chords in a disk-like manifold.
method Study of Finsler geodesic chords under reversibility assumption.
result At least N orthogonal Finsler geodesic chords found in a disk-like manifold.

To any generic curve in an oriented surface there corresponds an oriented chord diagram, and any oriented chord diagram may be realized by a curve in some oriented surface. The genus of an oriented chord diagram is the minimal genus of an oriented surface in which it may be realized. Let g_n denote the expected genus o…

2009-04-28abs ↗pdf ↗

In view of the result of Kontsevich, now often called ``the fundamental theorem of Vassiliev theory'', identifying the graded dual of the associated graded vector space to the space of Vassiliev invariants filtered by degree with the linear span of chord diagrams modulo the ``4T-relation'' (and in the unframed case, th…

2008-01-21abs ↗pdf ↗

It is known that the totally umbilical hypersurfaces in the (n+1)-dimensional spheres are characterized as the only hypersurfaces with weak stability index 0. That is, a compact hypersurface with constant mean curvature, cmc, in S^{n+1}, different from an Euclidean sphere, must have stability index greater than or equa…

2012-02-09abs ↗pdf ↗

The study finds at least two short, simple geodesic chords on a disk with convex boundary.

problem Existence of short, simple geodesic chords on a 2-disk with convex boundary.
method Proof of existence using Riemannian geometry and bounds on lengths.
result Existence of at least two short, simple orthogonal geodesic chords on a 2-disk with convex boundary.

The paper proves the existence and properties of geodesics on convex surfaces.

problem Existence and properties of geodesics on convex surfaces with free boundaries.
method Free boundary curve shortening flow on closed surfaces with strictly convex boundary.
result Existence of two free boundary embedded geodesics and geodesics with Morse Index 1 and 2.

Vassiliev invariants can be studied by studying the spaces of chord diagrams associated with singular knots. To these chord diagrams are associated the intersection graphs of the chords. We extend results of Chmutov, Duzhin and Lando to show that these graphs determine the chord diagram if the graph has at most one loo…

1998-07-08abs ↗pdf ↗

The paper calculates a specific weight system for chord diagrams with a particular graph structure.

problem Calculating a specific weight system for chord diagrams with a complete bipartite graph structure.
method Using a Lie algebra sl3\mathfrak{sl}_3 and its weight system, the authors derive a function on chord diagrams.
result The authors compute the sl3\mathfrak{sl}_3 weight system for chord diagrams with a complete bipartite graph structure.

We introduce a new geometric flow called the chord shortening flow which is the negative gradient flow for the length functional on the space of chords with end points lying on a fixed submanifold in Euclidean space. As an application, we give a simplified proof of a classical theorem of Lusternik and Schnirelmann (and…

2017-07-13abs ↗pdf ↗

The paper finds an upper limit for the length of geodesic chords on Riemannian manifolds.

problem Finding the maximum length of geodesic chords on Riemannian manifolds.
method Establishing an upper bound for geodesic chord length using geometric bounds on the manifold.
result An upper bound for the length of geodesic chords is derived, with a specific example for 2-dimensional spheres.

For any chord diagram on a circle there exists a complete graph on sufficiently many vertices such that any generic immersion of it to the plane contains a plane closed curve whose chord diagram contains the given chord diagram as a sub-chord diagram. For any generic immersion of the complete graph on six vertices to t…

2012-10-27abs ↗pdf ↗

Study on curve shortening flow with boundary conditions, proving convergence or contraction.

problem Analyzing curve shortening flow with free boundaries.
method Introduced a reflected chord-arc profile and obtained chord-arc estimates.
result Proved that flows either converge to a critical chord or contract to a round half-point.

The paper proves stability of critical points for conformally invariant Lagrangians.

problem Stability of critical points for conformally invariant Lagrangians under weak convergence.
method Upper-semi-continuity of Morse index plus nullity established for critical points.
result The sum of Morse indices and nullity is bounded from above by the sum of the Morse indices plus the nullity of the weak limit and bubbles.

In previous work, we defined the intersection graph of a chord diagram associated with a string link (as in the theory of finite type invariants). In this paper, we look at the case when this graph is a tree, and we show that in many cases these trees determine the chord diagram (modulo the usual 1-term and 4-term rela…

2004-08-20abs ↗pdf ↗

Paper shows how to represent Milnor's triple linking number using chord diagrams and doodle invariants.

problem Tackles the representation of Milnor's triple linking number.
method Establishes an analogous description for Milnor's triple linking number using counts of chord diagrams and doodle invariants.
result Shows that Milnor's triple linking number can be represented in terms of chord diagrams and doodle invariants.

Chord diagrams on circles and their intersection graphs (also known as circle graphs) have been intensively studied, and have many applications to the study of knots and knot invariants, among others. However, chord diagrams on more general graphs have not been studied, and are potentially equally valuable in the study…

2005-08-15abs ↗pdf ↗