scholarly journals ON VIRTUAL CROSSING NUMBER ESTIMATES FOR VIRTUAL LINKS

2009 ◽  
Vol 18 (06) ◽  
pp. 757-772 ◽  
Author(s):  
DENIS MIKHAILOVICH AFANASIEV ◽  
VASSILY OLEGOVICH MANTUROV
Keyword(s):  
Infinite Series ◽  
Crossing Number ◽  
Virtual Knot ◽  
Virtual Knots ◽  
Crossing Numbers ◽  
Virtual Links ◽  
Knot Diagrams ◽  
Extremal Properties

Considering extremal properties of one polynomial of virtual knots, we establish estimates for virtual crossing numbers of virtual knots from a given class. This yields minimality of certain diagrams of virtual knots with respect to the virtual crossing number. Infinite series of pairwise distinct minimal virtual knot diagrams are constructed and their properties are discussed.

A PARITY AND A MULTI-VARIABLE POLYNOMIAL INVARIANT FOR VIRTUAL LINKS

2013 ◽  
Vol 22 (13) ◽  
pp. 1350073 ◽  
Author(s):  
YOUNG HO IM ◽  
KYOUNG IL PARK
Keyword(s):  
Knot Theory ◽  
Virtual Link ◽  
Polynomial Invariant ◽  
Polynomial Invariants ◽  
Virtual Knot ◽  
Virtual Knots ◽  
Link Diagrams ◽  
Virtual Links ◽  
Knot Diagrams

We introduce a parity of classical crossings of virtual link diagrams which extends the Gaussian parity of virtual knot diagrams and the odd writhe of virtual links that extends that of virtual knots introduced by Kauffman [A self-linking invariants of virtual knots, Fund. Math.184 (2004) 135–158]. Also, we introduce a multi-variable polynomial invariant for virtual links by using the parity of classical crossings, which refines the index polynomial introduced in [Index polynomial invariants of virtual links, J. Knot Theory Ramifications19(5) (2010) 709–725]. As consequences, we give some properties of our invariant, and raise some examples.

scholarly journals FILAMENTATIONS FOR VIRTUAL LINKS

2006 ◽  
Vol 15 (03) ◽  
pp. 327-338 ◽  
Author(s):  
WILLIAM J. SCHELLHORN
Keyword(s):  
Virtual Knot ◽  
Virtual Knots ◽  
Chord Diagrams ◽  
Virtual Links ◽  
Knot Diagrams

In 2002, Hrencecin and Kauffman defined a filamentation invariant on oriented chord diagrams that may determine whether the corresponding flat virtual knot diagrams are non-trivial. A virtual knot diagram is non-classical if its related flat virtual knot diagram is non-trivial. Hence filamentations can be used to detect non-classical virtual knots. We extend these filamentation techniques to virtual links with more than one component. We also give examples of virtual links that they can detect as non-classical.

scholarly journals VIRTUAL CROSSING NUMBERS FOR VIRTUAL KNOTS

2012 ◽  
Vol 21 (13) ◽  
pp. 1240009
Author(s):  
VASSILY OLEGOVICH MANTUROV
Keyword(s):  
Crossing Number ◽  
Virtual Knot ◽  
Virtual Knots ◽  
Crossing Numbers

The aim of the present paper is to prove that the minimal number of virtual crossings for some families of virtual knots grows quadratically with respect to the minimal number of classical crossings. All previously known estimates for virtual crossing number ([D. M. Afanasiev, Refining the invariants of virtual knots by using parity, Sb. Math.201(6) (2010) 3–18; H. A. Dye and L. H. Kauffman, Virtual crossing numbers and the arrow polynomial, in The Mathematics of Knots. Theory and Applications, eds. M. Banagl and D. Vogel (Springer-Verlag, 2010); S. Satoh and Y. Tomiyama, On the crossing number of a virtual knot, Proc. Amer. Math. Soc.140 (2012) 367–376] and so on) were principally no more than linear in the number of classical crossings (or, what is the same, in the number of edges of a virtual knot diagram) and no virtual knot was found with virtual crossing number greater than the classical crossing number.

Characterization of signed Gauss paragraphs and skew-symmetric graded matrices

2018 ◽  
Vol 27 (01) ◽  
pp. 1850002 ◽  
Author(s):  
José Gregorio Rodríguez-Nieto
Keyword(s):  
Embedded Graphs ◽  
Intersection Pairing ◽  
Virtual Knot ◽  
Virtual Knots ◽  
Virtual Links ◽  
The One ◽  
Minimal Realizations ◽  
Knot Diagrams ◽  
Bracket Polynomials

In this paper, we use theory of embedded graphs on oriented and compact [Formula: see text]-surfaces to construct minimal realizations of signed Gauss paragraphs. We prove that the genus of the ambient surface of these minimal realizations can be seen as a function of the maximum number of Carter’s circles. For the case of signed Gauss words, we use a generating set of [Formula: see text], given in [G. Cairns and D. Elton, The Planarity problem for signed Gauss world, J. Knots Theor. Ramif. 2(4) (1993) 359–367], and the intersection pairing of immersed [Formula: see text]-normal curves to present a short solution of the signed Gauss word problem. We relate this solution with the one given by Cairns and Elton. Moreover, we define the join operation on signed Gauss paragraphs to produce signed Gauss words such that both can be realized on the same minimal genus [Formula: see text]-surface. We connect the characterization of signed Gauss paragraph with the recognition virtual links problem. Also we present a combinatorial algorithm to compute, in an easier way, skew-symmetric graded matrices [V. Turaev, Cobordism of knots on surfaces, J. Topol. 1(2) (2008) 285–305] for virtual knots through the concept of triplets [M. Toro and J. Rodríguez, Triplets associated to virtual knot diagrams, Rev. Integración (2011)]. Therefore, we can prove that the Kishino’s knot is not classical, moreover, we prove that the virtual knots of the family [Formula: see text] given in [H. A. Dye, Virtual knots undetected by [Formula: see text] and [Formula: see text]-strand bracket polynomials, Topol. Appl. 153 (2005) 141–160] are not classical knots.

Polynomial invariants of flat virtual links using invariants of virtual links

2015 ◽  
Vol 24 (06) ◽  
pp. 1550036 ◽  
Author(s):  
Joonoh Kim ◽  
Sang Youl Lee
Keyword(s):  
Crossing Number ◽  
Polynomial Invariant ◽  
Polynomial Invariants ◽  
Virtual Knot ◽  
Virtual Knots ◽  
Virtual Links ◽  
Integer Labeling

In this paper, we describe a method of making a polynomial invariant of flat virtual knots in terms of an integer labeling of the flat virtual knot diagram and an invariant of virtual links. We show that the polynomial is sometimes useful to detect non-invertibility and also to determine the virtual crossing number of a given flat virtual knot.

STABLE EQUIVALENCE OF KNOTS ON SURFACES AND VIRTUAL KNOT COBORDISMS

2002 ◽  
Vol 11 (03) ◽  
pp. 311-322 ◽  
Author(s):  
J. SCOTT CARTER ◽  
SEIICHI KAMADA ◽  
MASAHICO SAITO
Keyword(s):  
Equivalence Relation ◽  
Equivalence Classes ◽  
Virtual Knot ◽  
Virtual Knots ◽  
Link Homology ◽  
Stable Equivalence ◽  
Virtual Links ◽  
Curves On Surfaces ◽  
Immersed Curves ◽  
Knot Diagrams

We introduce an equivalence relation, called stable equivalence, on knot diagrams and closed generically immersed curves on surfaces. We give bijections between the set of abstract knots, the set of virtual knots, and the set of the stable equivalence classes of knot diagrams on surfaces. Using these bijections, we define concordance and link homology for virtual links. As an application, it is shown that Kauffman's example of a virtual knot diagram is not equivalent to a classical knot diagram.

A MULTI-VARIABLE POLYNOMIAL INVARIANT FOR UNORIENTED VIRTUAL KNOTS AND LINKS

2009 ◽  
Vol 18 (05) ◽  
pp. 625-649 ◽  
Author(s):  
YASUYUKI MIYAZAWA
Keyword(s):  
Crossing Number ◽  
Weighted Sum ◽  
Virtual Link ◽  
Polynomial Invariant ◽  
Virtual Knots ◽  
Virtual Links ◽  
Knots And Links

We construct a multi-variable polynomial invariant Y for unoriented virtual links as a certain weighted sum of polynomials, which are derived from virtual magnetic graphs with oriented vertices, on oriented virtual links associated with a given virtual link. We show some features of the Y-polynomial including an evaluation of the virtual crossing number of a virtual link.

SOME NUMERICAL INVARIANTS OF FLAT VIRTUAL LINKS ARE ALWAYS REALIZED BY REDUCED DIAGRAMS

2006 ◽  
Vol 15 (03) ◽  
pp. 289-297 ◽  
Author(s):  
TERUHISA KADOKAMI
Keyword(s):  
Intersection Number ◽  
Finite Sequence ◽  
Closed Surface ◽  
Crossing Number ◽  
The Self ◽  
Virtual Link ◽  
Virtual Knot ◽  
Virtual Links ◽  
Geodesic Loop ◽  
Numerical Invariants

Any flat virtual link has a reduced diagram which satisfies a certain minimality, and reduced diagrams are related one another by a finite sequence of a certain Reidemeister move. The move preserves some numerical invariants of diagrams. So we can define numerical invariants for flat virtual links. One of them, the crossing number of a flat virtual knot K, coinsides with the self-intersection number of K as an essential geodesic loop on a hyperbolic closed surface. We also show an equation among these numerical invariants, basic properties by using the equation, and determine non-split flat virtual links with the crossing number up to three.

Picture-valued parity-biquandle bracket

2020 ◽  
Vol 29 (02) ◽  
pp. 2040004 ◽  
Author(s):  
Denis P. Ilyutko ◽  
Vassily O. Manturov
Keyword(s):  
Classical Case ◽  
Linear Combinations ◽  
Virtual Knot ◽  
Virtual Knots ◽  
Underlying Graph ◽  
Kauffman Bracket ◽  
Knot Diagrams

In V. O. Manturov, On free knots, preprint (2009), arXiv:math.GT/0901.2214], the second named author constructed the bracket invariant [Formula: see text] of virtual knots valued in pictures (linear combinations of virtual knot diagrams with some crossing information omitted), such that for many diagrams [Formula: see text], the following formula holds: [Formula: see text], where [Formula: see text] is the underlying graph of the diagram, i.e. the value of the invariant on a diagram equals the diagram itself with some crossing information omitted. This phenomenon allows one to reduce many questions about virtual knots to questions about their diagrams. In [S. Nelson, M. E. Orrison and V. Rivera, Quantum enhancements and biquandle brackets, preprint (2015), arXiv:math.GT/1508.06573], the authors discovered the following phenomenon: having a biquandle coloring of a certain knot, one can enhance various state-sum invariants (say, Kauffman bracket) by using various coefficients depending on colors. Taking into account that the parity can be treated in terms of biquandles, we bring together the two ideas from these papers and construct the picture-valued parity-biquandle bracket for classical and virtual knots. This is an invariant of virtual knots valued in pictures. Both the parity bracket and Nelson–Orrison–Rivera invariants are partial cases of this invariant, hence this invariant enjoys many properties of various kinds. Recently, the authors together with E. Horvat and S. Kim have found that the picture-valued phenomenon works in the classical case.

INVARIANTS OF FLAT VIRTUAL LINKS INDUCED FROM VASSILIEV INVARIANTS OF DEGREE ONE FOR VIRTUAL LINKS

2011 ◽  
Vol 20 (12) ◽  
pp. 1649-1667 ◽  
Author(s):  
YOUNG HO IM ◽  
SERA KIM ◽  
KYEONGHUI LEE
Keyword(s):  
Vassiliev Invariants ◽  
Virtual Knot ◽  
Virtual Knots ◽  
Virtual Links

We introduce invariants of flat virtual links which are induced from Vassiliev invariants of degree one for virtual links. Also we give several properties of these invariants for flat virtual links and examples. In particular, if the value of some invariants of flat virtual knots F are non-zero, then F is non-invertible so that every virtual knot overlying F is non-invertible.

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