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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 signature of knots

To each unit complex number with positive imaginary part there is defined a Tristram-Levine knot signature function. The set of all such signature functions is linearly independent as a set of functions defined on the set of all knots. The set of averaged signature functions forms a linearly independent set of homomoro…

2002-08-28abs ↗pdf ↗

The paper introduces signatures for virtual knots and applies them to study concordance.

problem Investigating the concordance of virtual knots and their slice genus.
method Defined Tristram-Levine signatures for almost classical knots, used Seifert pairing, and introduced parity projection.
result Established slice obstructions for all virtual knots and determined slice status for almost classical knots.

The paper studies twisted signature invariants of fibered knots and 3-manifolds.

problem Computing twisted signature invariants of fibered knots and 3-manifolds.
method Reduction to the study of the intersection form and monodromy on the twisted homology of the fiber surface. Use of rings of power series to interpret the twisted Milnor pairing and relate it to twisted Blanchfield pairings.
result New twisted generalizations of the Levine-Tristram signature are derived.

We study properties of the signature function of the torus knot Tp,qT_{p,q}. First we provide a very elementary proof of the formula for the integral of the signatures over the circle. We obtain also a closed formula for the Tristram--Levine signature of a torus knot in terms of Dedekind sums.

2010-02-24abs ↗pdf ↗

We define a set of "second-order" L^(2)-signature invariants for any algebraically slice knot. These obstruct a knot's being a slice knot and generalize Casson-Gordon invariants, which we consider to be "first-order signatures". As one application we prove: If K is a genus one slice knot then, on any genus one Seifert …

2008-08-11abs ↗pdf ↗

The paper calculates knot invariants using Blanchfield forms and obstructs sliceness.

problem Computing and obstructing the sliceness of knots.
method Algorithmic computation of twisted signature invariants using twisted Blanchfield forms and satellite formulas.
result Illustrated algorithm for (2,q)(2,q)-torus knots and obstruction of sliceness for certain knots.

We analyze properties of links which have diagrams with a small number of negative crossings. We show that if a nontrivial link has a diagram with all crossings positive except possibly one, then the signature of the link is negative. If a link diagram has two negative crossings, we show that the signature of the link …

2009-04-27abs ↗pdf ↗

It was asked by J.Birman, Williams, and L.Rudolph whether nontrivial Lorentz knots have always positive signature. Lorentz knots are examples of positive braids (in our convention they have all crossings negative so they are negative links). It was shown by L.Rudolph that positive braids have positive signature (if the…

2009-05-06abs ↗pdf ↗

The paper studies twisted signature invariants and their relation to Casson-Gordon invariants.

problem Obstructions to knot concordance using twisted signature invariants.
method Defining a twisted signature function σ_{K,ρ} and proving satellite formulas.
result The twisted signature function σ_{K,ρ} is closely related to Casson-Gordon invariants for appropriate metabelian representations.

Classifies real rational knots and curves in a specific quadric space.

problem Classifying real rational knots and curves in a quadric space of signature (3,2)(3,2).
method Classification through a study of real rational curves of low degree in the quadric.
result Provides representatives of all real rational knots of degree 5\leq 5 in the quadric.

The dihedral genus of a knot is related to its signature and minimal surface genus.

problem Determining the dihedral genus of knots and its relation to signatures and minimal surface genus.
method Using dihedral branched covers and properties of Fox colorings, the dihedral genus is linked to the signature of the cover and the Murasugi signature of the knot.
result An infinite family of knots with minimal genus surfaces that realize the four-genus of the knot.

The Kashaev conjecture is proven for classical signatures and Alexander polynomials of links.

problem Proving the Kashaev conjecture for signatures and Alexander polynomials.
method Relating Kashaev's matrix to Gordon-Litherland's work and Kauffman's model.
result Proven Alexander polynomial and classical signature parts of the conjecture for arbitrary links, and full conjecture for definite knots.

The signature function of a knot is a locally constant integer valued function with domain the unit circle. The jumps (i.e., the discontinuities) of the signature function can occur only at the roots of the Alexander polynomial on the unit circle. The latter are important in deforming U(1) representations of knot group…

2003-10-14abs ↗pdf ↗

This paper computes Jones polynomials and Khovanov homology for weaving knots.

problem Computing Jones polynomials and Khovanov homology for weaving knots.
method Developed recursion relations and used additional results to compute ranks of Khovanov homology.
result Computed ranks of Khovanov homology for W(3,n)W(3,n) knots and provided evidence for normal distribution of ranks.

Ascending numbers are determined for 64 knots with at most n=10 crossings. After proving the theorem about the signature of alternating knot families, we distinguished all families of knots obtained from generating alternating knots with at most 10 crossings, for which the unknotting number can be confirmed by using th…

2011-07-10abs ↗pdf ↗

According to a formula by Gordon and Litherland, the signature of a knot K can be computed as the signature of a Goeritz matrix of K minus a suitable correction term, read off from the diagram of K. In this article, we consider the family of two bridge knots K(p/q) and compute the signature of their Goeritz matrices in…

2009-10-15abs ↗pdf ↗

We use the knot filtration on the Heegaard Floer complex to define an integer invariant tau(K) for knots. Like the classical signature, this invariant gives a homomorphism from the knot concordance group to Z. As such, it gives lower bounds for the slice genus (and hence also the unknotting number) of a knot; but unlik…

2003-01-14abs ↗pdf ↗

We use twisted Alexander polynomials to show that certain algebraically slice 2-bridge knots are not topologically slice, even though all prime power Casson-Gordon signatures vanish. We also provide some computations indicating the efficacy of Casson-Gordon signatures in obstructing the smooth sliceness of 2-bridge kno…

2015-07-06abs ↗pdf ↗