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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.

168,657 papers · 148 categories

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48 results for Isotopy

In this paper we solve the following problem in the affirmative: Let ZZ be a continuum in the plane $\complex$ and suppose that $h:Z\times [0,1]\to\complex$ is an isotopy starting at the identity. Can hh be extended to an isotopy of the plane? We will provide a new characterization of an accessible point in a planar …

2008-11-03abs ↗pdf ↗

A star-like isotopy for oriented links in 3-space is an isotopy which uses only Reidemeister II moves with opposite orientations and Reidemeister III moves with alternating orientations when checking the strands clockwise (or anticlockwise). We define a link polynomial derived from the Jones polynomial which is, in gen…

2008-04-08abs ↗pdf ↗

Uniform convergence of isotopies implies ambient isotopy, aiding knot equivalence.

problem Determining when uniform convergence of isotopies leads to ambient isotopies.
method Using a diagrammatic condition to offload uniform convergence, constructing examples of tame knots.
result Constructing tame knots with countably-many crossings, distinguishing them from wild curves.

Improved proofs for topological and smooth pseudo-isotopies of simply connected 4-manifolds.

problem Proving topological and smooth pseudo-isotopies of simply connected 4-manifolds.
method Provided different arguments that bypass the replacement criterion, thus completing Quinn's proofs.
result Corrected and completed Quinn's proofs of both topological and stable smooth pseudo-isotopy theorems.

The study constructs examples of pseudo-isotopic but not isotopic 4-manifold diffeomorphisms.

problem Understanding pseudo-isotopy and its relation to isotopy for 4-manifolds.
method Construction of examples and analysis of pseudo-isotopy obstructions.
result Not all pseudo-isotopic diffeomorphisms are isotopic, providing new insights into 4-manifold topology.

In this paper we define and study flexible links and flexible isotopy in projective space. Flexible links are meant to capture the topological properties of real algebraic links. We classify all flexible links up to flexible isotopy using Ekholms interpretation of Viros encomplexed writhe.

2012-12-15abs ↗pdf ↗

This paper introduces two virtual knot theory ``analogues'' of a well-known family of invariants for knots in thickened surfaces: the Grishanov-Vassiliev finite-type invariants of order two. The first, called the three loop isotopy invariant, is an invariant of virtual knots while the second, called the three loop fram…

2013-09-11abs ↗pdf ↗

The symplectic isotopy conjecture states that every smooth symplectic surface in CP2CP^2 is symplectically isotopic to a complex algebraic curve. Progress began with Gromov's pseudoholomorphic curves [Gro85], and progressed further culminating in Siebert and Tian's proof of the conjecture up to degree 17 [ST05], but fur…

2017-09-08abs ↗pdf ↗

We define an equivalence relation called A-isotopy between finitely determined map-germs, which is a strengthened version of A-equivalence. We consider the number of A-isotopy classes of equidimensional Morin singularities, and some other well-known low-dimensional singularities. We also give an application to stable p…

2015-10-13abs ↗pdf ↗

Study isotopy and concordance for metrics on manifolds with boundary.

problem Understanding isotopy and concordance for metrics on manifolds with boundary.
method Developed tools for studying isotopy and concordance, introduced variants of minimal concordance.
result Obtained a complete picture for surfaces, introduced new variants of concordance.

This paper investigates dynamics that persist under isotopy in classes of orientation-preserving homeomorphisms of orientable surfaces. The persistence of periodic points with respect to periodic and strong Nielsen equivalence is studied. The existence of a dynamically minimal representative with respect to these relat…

1999-04-28abs ↗pdf ↗

Constructs pseudo-isotopies with Cerf diagrams and Hatcher-Wagoner invariants for barbell maps.

problem Understanding and constructing pseudo-isotopies for barbell maps.
method Constructs specific pseudo-isotopies with Cerf diagrams and Hatcher-Wagoner invariants.
result Every pseudo-isotopy with vanishing first Hatcher-Wagoner invariant can be isotoped to a composition of standard barbell pseudo-isotopies.

We present a grid diagram analogue of Carter, Rieger and Saito's smooth movie theorem. Specifically, we give definitions for grid movies, grid movie isotopies and present a definition of grid planar isotopy as a particular subset of the grid diagram moves: stabilization, destabilization and commutation. We show that gr…

2013-03-07abs ↗pdf ↗

We call two Engel structures isotopic if they are homotopic through Engel structures by a homotopy that fixes the characteristic line field. In the present paper we define an isotopy invariant of Engel structures on oriented circle bundles over closed oriented three-manifolds and apply it to give an isotopy classificat…

2012-09-06abs ↗pdf ↗

This is the less official, English version of the proof of the fact that every closed atoroidal 3-manifold carries finitely many isotopy classes of tight contact structures.

2003-05-14abs ↗pdf ↗

Geometric aspects of the filtration on classical links by k-quasi-isotopy are discussed, including the effect of Whitehead doubling, relations with Smythe's n-splitting and Kobayashi's k-contractibility. One observation is: ω-quasi-isotopy is equivalent to PL isotopy for links in a homotopy 3-sphere (resp. contractible…

2001-03-18abs ↗pdf ↗

The paper studies pseudo-isotopies of spherical 3-manifolds and computes ranks of certain groups.

problem Computing ranks of abelian groups related to spherical 3-manifolds.
method Surgery on theta-graphs embedded in spherical 3-manifolds, study of pseudo-isotopy behavior under suspension.
result Lower bounds of ranks of abelian groups π0Diff(X,)π_0\mathrm{Diff}(X,\partial) are computed.

The inclusion of the space of all knots of a prescribed writhe in a particular isotopy class into the space of all knots in that isotopy class is a weak homotopy equivalence.

1999-05-25abs ↗pdf ↗

We study virtual isotopy sequences with classical initial and final diagrams, asking when such a sequence can be changed into a classical isotopy sequence by replacing virtual crossings with classical crossings. An example of a sequence for which no such virtual crossing realization exists is given. A conjecture on con…

2003-03-06abs ↗pdf ↗

In part I it was shown that for each k>0 the generalized Sato-Levine invariant detects a gap between k-quasi-isotopy of link and peripheral structure preserving isomorphism of the finest quotient G_k of its fundamental group, `functorially' invariant under k-quasi-isotopy. Here we show that Cochran's derived invariant …

2002-01-04abs ↗pdf ↗

All knots are fused isotopic to the unknot via a process known as virtualization. We extend and adapt this process to show that, up to fused isotopy, classical links are classified by their linking numbers.

2006-06-08abs ↗pdf ↗