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We introduce an algebraic structure we call semiquandles whose axioms are derived from flat Reidemeister moves. Finite semiquandles have associated counting invariants and enhanced invariants defined for flat virtual knots and links. We…

Geometric Topology · Mathematics 2011-09-20 Allison Henrich , Sam Nelson

We show that any two diagrams of the same knot or link are connected by a sequence of Reidemeister moves which are sorted by type.

Geometric Topology · Mathematics 2009-04-22 Alexander Coward

We construct the new non-trivial state--sum invariants for virtual knots and links by a generalization of the powerful Carter--Saito--Jelsovsky--Kamada--Langford theorem for classical knots. The main result of this work is based on…

Quantum Algebra · Mathematics 2023-07-06 A. A. Kazakov

In this paper, we establish that the arc shift operation on a $n$-component virtual link diagram acts as an unknotting operation when the virtual link is $n$-homogeneous proper, aiding in the classification of \( n \)-component virtual…

Geometric Topology · Mathematics 2025-02-14 Aastha Sahore , Komal Negi , Amrender Singh Gill , Madeti Prabhakar

We discuss Vassiliev invariants for virtual knots, expanding upon the theory of quantum virtual knot invariants developed in arXiv:1509.00578. In particular, following the theory of quantum invariants we work with 'rotational' virtual…

Geometric Topology · Mathematics 2022-09-20 Wout Moltmaker , Louis H. Kauffman

Two natural generalizations of knot theory are the study of spatially embedded graphs, and Kauffman's theory of virtual knots. In this paper we combine these approaches to begin the study of virtual spatial graphs.

Geometric Topology · Mathematics 2009-01-10 Thomas Fleming , Blake Mellor

We consider Milnor invariants for certain covering links as a generalization of covering linkage invariants formulated by R. Hartley and K. Murasugi. A set of Milnor invariants for covering links is a cobordism invariant of a link, and that…

Geometric Topology · Mathematics 2016-03-21 Natsuka Kobayashi , Kodai Wada , Akira Yasuhara

This paper discusses a generalization of virtual knot theory that we call multi-virtual knot theory. Multi-virtual knot theory uses a multiplicity of types of virtual crossings. As we will explain, this multiplicity is motivated by the way…

Geometric Topology · Mathematics 2026-03-17 Louis H Kauffman

In this note we present a combinatorial link invariant that underlies some recent stable homotopy refinements of Khovanov homology of links. The invariant takes the form of a functor between two combinatorial 2-categories, modulo a notion…

Geometric Topology · Mathematics 2021-11-16 Tyler Lawson , Robert Lipshitz , Sucharit Sarkar

Pseudo links generalize classical links by allowing crossings with missing over/under information, called pre-crossings. While the pseudo braid framework provides an algebraic description of pseudo links via a Markov-type theorem, the…

Geometric Topology · Mathematics 2026-05-05 Ioannis Diamantis

We obtain Polyak-Viro type formula for the Milnor triple linking number that can be applied to diagrams with triple or more multiple-crossings. The proof is based on the idea of Brooks and Komendarczyk, but is different from theirs in that…

Geometric Topology · Mathematics 2025-03-31 Yusaku Okuhara , Keiichi Sakai

We present a new link invariant which depends on a representation of the link group in SO(3). The computer calculations indicate that an abelian version of this invariant is expressed in terms of the Alexander polynomial of the link. On the…

Geometric Topology · Mathematics 2007-05-23 Evgeniy V. Martyushev

We characterize the virtual link invariants that can be described as partition function of a real-valued R-matrix, by being weakly reflection positive. Weak reflection positivity is defined in terms of joining virtual link diagrams, which…

Quantum Algebra · Mathematics 2015-03-09 Guus Regts , Alexander Schrijver , Bart Sevenster

A rational knot or link can be put into a standard alternating format which has horizontal and vertical twist sites (double helices). The number and type of these twist sites are determined by terms of next-to-highest $z$-degree in…

Geometric Topology · Mathematics 2014-10-02 Mark E. Kidwell , Kerry M. Luse

It is known that the Kauffman-Murasugi-Thislethwaite type inequality becomes an equality for any (possibly virtual) adequate link diagram. We refine this condition. As an application we obtain a criterion for virtual link diagram with…

Geometric Topology · Mathematics 2021-03-29 Minori Okamura , Keiichi Sakai

Three-component links in the 3-dimensional sphere were classified up to link homotopy by John Milnor in his senior thesis, published in 1954. A complete set of invariants is given by the pairwise linking numbers p, q and r of the…

Geometric Topology · Mathematics 2021-08-12 Dennis DeTurck , Herman Gluck , Rafal Komendarczyk , Paul Melvin , Clayton Shonkwiler , David Shea Vela-Vick

We consider the question of which virtual knots have finite fundamental medial bikei. We describe and implement an algorithm for completing a presentation matrix of a medial bikei to an operation table, determining both the cardinality and…

Geometric Topology · Mathematics 2017-04-05 Julien Chien , Sam Nelson

In [14], the second named author constructed the bracket invariant [.] of virtual knots valued in pictures (linear combinations of virtual knot diagrams with some crossing information omitted), such that for many diagrams K, the following…

Geometric Topology · Mathematics 2017-01-24 Denis P. Ilyutko , Vassily O. Manturov

We define a multi-variable version of the Affine Index Polynomial for virtual links. This invariant reduces to the original Affine Index Polynomial in the case of virtual knots, and also generalizes the version for compatible virtual links…

Geometric Topology · Mathematics 2019-09-11 Nicolas Petit

We define the virtual bridge number $vb(K)$ and the virtual unknotting number $vu(K)$ invariants for virtual knots. For ordinary knots $K$ they are closely related to the bridge number $b(K)$ and the unknotting number $u(K)$ and we have…

Geometric Topology · Mathematics 2014-04-24 Evarist Byberi , Vladimir Chernov