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Related papers: Psyquandles, Singular Knots and Pseudoknots

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We enhance the psyquandle counting invariant for singular knots and pseudoknots using quivers analogously to quandle coloring quivers. This enables us to extend the in-degree polynomial invariants from quandle coloring quiver theory to the…

Geometric Topology · Mathematics 2021-07-14 Jose Ceniceros , Anthony Christiana , Sam Nelson

We bring cocycle enhancement theory to the case of psyquandles. Analogously to our previous work on virtual biquandle cocycle enhancements, we define enhancements of the psyquandle counting invariant via pairs of a biquandle 2-cocycle and a…

Geometric Topology · Mathematics 2020-10-01 Jose Ceniceros , Sam Nelson

In this short survey we review recent results dealing with algebraic structures (quandles, psyquandles, and singquandles) related to singular knot theory. We first explore the singquandles counting invariant and then consider several recent…

Geometric Topology · Mathematics 2021-03-10 Jose Ceniceros , Indu R. Churchill , Mohamed Elhamdadi , Mustafa Hajij

We generalize the notion of the quandle polynomial to the case of singquandles. We show that the singquandle polynomial is an invariant of finite singquandles. We also construct a singular link invariant from the singquandle polynomial and…

Geometric Topology · Mathematics 2021-01-21 Jose Ceniceros , Indu R. Churchill , Mohamed Elhamdadi

The Alexander biquandle of a virtual knot or link is a module over a 2-variable Laurent polynomial ring which is an invariant of virtual knots and links. The elementary ideals of this module are then invariants of virtual isotopy which…

Geometric Topology · Mathematics 2013-09-30 Alissa S. Crans , Allison Henrich , Sam Nelson

We extend the notion of biquandle brackets to the case of psyquandles, defining quantum enhancements of the psyquandle counting invariant for singular knots and pseudoknots. We provide examples to illustrate the computation of these…

Geometric Topology · Mathematics 2025-08-20 Sam Nelson , Natsumi Oyamaguchi

We explore a knot invariant derived from colorings of corresponding $1$-tangles with arbitrary connected quandles. When the quandle is an abelian extension of a certain type the invariant is equivalent to the quandle $2$-cocycle invariant.…

Geometric Topology · Mathematics 2016-08-09 W. Edwin Clark , Larry A. Dunning , Masahico Saito

This paper discusses the construction of a generalized Alexander polynomial for virtual knots and links, and the reformulation of this invariant as a quantum link invariant. The algebraic background for the generalized Alexander module is…

Geometric Topology · Mathematics 2007-05-23 Louis H. Kauffman , David E. Radford

We introduce shadow structures for singular knot theory. Precisely, we define \emph{two} invariants of singular knots and links. First, we introduce a notion of action of a singquandle on a set to define a shadow counting invariant of…

Geometric Topology · Mathematics 2021-01-22 Jose Ceniceros , Indu R. Churchill , Mohamed Elhamdadi

Biquandle brackets define invariants of classical and virtual knots and links using skein invariants of biquandle-colored knots and links. Biquandle coloring quivers categorify the biquandle counting invariant in the sense of defining…

Geometric Topology · Mathematics 2021-09-14 Pia Cosma Falkenburg , Sam Nelson

The Alexander polynomial of a knot has been generalized in three different ways to give twisted invariants. The resulting invariants are usually referred to as twisted Alexander polynomials, higher-order Alexander polynomials and…

Geometric Topology · Mathematics 2014-10-28 Jérôme Dubois , Stefan Friedl , Wolfgang Lück

In this paper we introduce a new invariant of virtual knots and links that is non-trivial for infinitely many virtuals, but is trivial on classical knots and links. The invariant is initially be expressed in terms of a relative of the…

Geometric Topology · Mathematics 2007-05-23 Louis H. Kauffman

We extend the quandle cocycle invariant to oriented singular knots and links using algebraic structures called \emph{oriented singquandles} and assigning weight functions at both regular and singular crossings. This invariant coincides with…

Geometric Topology · Mathematics 2021-03-02 Jose Ceniceros , Indu R. Churchill , Mohamed Elhamdadi , Mustafa Hajij

We introduce an infinite family of quantum enhancements of the biquandle counting invariant we call biquandle virtual brackets. Defined in terms of skein invariants of biquandle colored oriented knot and link diagrams with values in a…

Geometric Topology · Mathematics 2019-08-28 Sam Nelson , Kanako Oshiro , Ayaka Shimizu , Yoshiro Yaguchi

We define invariants of oriented surface-links by enhancing the biquandle counting invariant using \textit{biquandle modules}, algebraic structures defined in terms of biquandle actions on commutative rings analogous to Alexander…

Geometric Topology · Mathematics 2019-08-28 Yewon Joung , Sam Nelson

We introduce two new families of polynomial invariants of oriented classical and virtual knots and links defined as decategorfications of the quandle coloring quiver. We provide examples to illustrate the computation of the invariants, show…

Geometric Topology · Mathematics 2025-08-18 Anusha Kabra , Sam Nelson

We introduce algebraic structures known as psybrackets and use them to define invariants of pseudoknots and singular knots and links. Psybrackets are Niebrzydowski tribrackets with additional structure inspired by the Reidemeister moves for…

Geometric Topology · Mathematics 2022-09-02 Suhyeon Jeong , Jieon Kim , Sam Nelson

In this paper we present a sequence of link invariants, defined from twisted Alexander polynomials, and discuss their effectiveness in distinguish knots. In particular, we recast and extend by geometric means a recent result of Silver and…

Geometric Topology · Mathematics 2018-12-24 Stefan Friedl , Stefano Vidussi

By considering a (not necessarily locally-flat) PL knot as the singular locus of a PL stratified pseudomanifold, we can use intersection homology theory to define intersection Alexander polynomials, a generalization of the classical…

Geometric Topology · Mathematics 2011-03-31 Greg Friedman

We use crossing parity to construct a generalization of biquandles for virtual knots which we call Parity Biquandles. These structures include all biquandles as a standard example referred to as the even parity biquandle. Additionally, we…

Geometric Topology · Mathematics 2011-03-16 Aaron Kaestner , Louis H. Kauffman
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