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We show that any virtual or welded period of a classical knot $K$ can be realized as a classical period. A direct consequence is that a classical knot admits only finitely many virtual or welded periods.

Geometric Topology · Mathematics 2021-03-16 Hans U. Boden , Andrew J. Nicas

The origin of light is a unsolved mystery in nature. Recently, it was suggested that light may originate from a new kind of order - quantum order. To test this idea in experiments, we study systems of screened magnetic/electric dipoles in…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Xiao-Gang Wen

We define new notions of groups of virtual and welded knots (or links) and we study their relations with other invariants, in particular the Kauffman group of a virtual knot.

Geometric Topology · Mathematics 2012-04-17 Valeriy G. Bardakov , Paolo Bellingeri

Shadows in videos are difficult to detect because of the large shadow deformation between frames. In this work, we argue that accounting for shadow deformation is essential when designing a video shadow detection method. To this end, we…

Computer Vision and Pattern Recognition · Computer Science 2023-03-28 Lihao Liu , Jean Prost , Lei Zhu , Nicolas Papadakis , Pietro Liò , Carola-Bibiane Schönlieb , Angelica I Aviles-Rivero

Shifts of finite type and the notion of shadowing, or pseudo-orbit tracing, are powerful tools in the study of dynamical systems. In this paper we prove that there is a deep and fundamental relationship between these two concepts. Let $X$…

Dynamical Systems · Mathematics 2017-02-20 Chris Good , Jonathan Meddaugh

This paper is an introduction to the subject of virtual knot theory, combined with a discussion of some specific new theorems about virtual knots. The new results are as follows: We prove, using a 3-dimensional topology approach that if a…

Geometric Topology · Mathematics 2007-05-23 Louis Kauffman , Vassily Olegovich Manturov

Motivated by inclination of the Earth's orbit that is not located at galactic plane for observing the shadow of Sgr A*, we consider the black hole shadow for arbitrary inclinations and different velocities of observers. A surprising finding…

General Relativity and Quantum Cosmology · Physics 2021-09-07 Zhe Chang , Qing-Hua Zhu

We introduce a new combinatorial method to encode knots and links with applications to knot invariants. Clasp diagrams defined in this paper are combinatorial blueprints for building knot diagrams out of full twists on two strings rather…

Geometric Topology · Mathematics 2019-11-11 Jacob Mostovoy , Michael Polyak

In this article we discuss applications of neural networks to recognising knots and, in particular, to the unknotting problem. One of motivations for this study is to understand how neural networks work on the example of a problem for which…

Geometric Topology · Mathematics 2022-11-28 L. H. Kauffman , N. E. Russkikh , I. A. Taimanov

We consider universal shot noise in ballistic chaotic cavities from a semiclassical point of view and show that it is due to action correlations within certain groups of classical trajectories. Using quantum graphs as a model system we sum…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Holger Schanz , Mathias Puhlmann , Theo Geisel

The motivation for this work is to construct a map from classical knots to virtual ones. What we get in the paper is a series of maps from knots in the full torus (thickened torus) to flat-virtual knots. We give definition of flat-virtual…

Geometric Topology · Mathematics 2024-06-21 V. O. Manturov , I. M. Nikonov

The dual to a tetrahedron consists of a single vertex at which four edges and six faces are incident. Along each edge, three faces converge. A 2-foam is a compact topological space such that each point has a neighborhood homeomorphic to a…

Geometric Topology · Mathematics 2012-10-15 J. Scott Carter

A virtual string can be defined as an equivalence class of planar diagrams under certain kinds of diagrammatic moves. Virtual strings are related to virtual knots in that a simple operation on a virtual knot diagram produces a diagram for a…

Geometric Topology · Mathematics 2009-09-29 Andrew Gibson

Given a group endowed with a Z/2-valued morphism we associate a Gauss diagram theory, and show that for a particular choice of the group these diagrams encode faithfully virtual knots on a given arbitrary surface. This theory contains all…

Geometric Topology · Mathematics 2014-03-17 Arnaud Mortier

Frame-spun knots are constructed by spinning a knot of lower dimension about a framed submanifold of S^n. We show that all frame-spun knots are slice (null-cobordant).

Geometric Topology · Mathematics 2011-03-31 Greg Friedman

We describe various properties and give several characterizations of ternary groups satisfying two axioms derived from the third Reidemeister move in knot theory. Using special attributes of such ternary groups, such as semi-commutativity,…

Group Theory · Mathematics 2019-10-29 Maciej Niebrzydowski , Agata Pilitowska , Anna Zamojska-Dzienio

Knot Theory is currently a very broad field. Even a long survey can only cover a narrow area. Here we concentrate on the path from Goeritz matrices to quasi-alternating links. On the way, we often stray from the main road and tell related…

Geometric Topology · Mathematics 2009-09-08 Jozef H. Przytycki

This paper proposes the definition of a quantum knot as a linear superposition of classical knots in three dimensional space. The definition is constructed and examples are discussed. Then the paper details extensions and also limitations…

Quantum Physics · Physics 2009-11-10 Louis H. Kauffman , Samuel J. Lomonaco

Shadows often occur when we capture the documents with casual equipment, which influences the visual quality and readability of the digital copies. Different from the algorithms for natural shadow removal, the algorithms in document shadow…

Computer Vision and Pattern Recognition · Computer Science 2024-06-19 Zinuo Li , Xuhang Chen , Chi-Man Pun , Xiaodong Cun

We present a marked analogue of Carter and Saito's movie theorem. Our definition of marking was chosen to coincide with the markings that arise in link Floer homology. In order to deal with complications arising from certain isotopies, we…

Geometric Topology · Mathematics 2018-01-04 Matthew Graham