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Related papers: Link invariants from finite biracks

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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

Niebrzydowski tribrackets are ternary operations on sets satisfying conditions obtained from the oriented Reidemeister moves such that the set of tribracket colorings of an oriented knot or link diagram is an invariant of oriented knots and…

Geometric Topology · Mathematics 2019-08-28 Deanna Needell , Sam Nelson , Yingqi Shi

Carter, Jelsovsky, Kamada, Langford and Saito have defined an invariant of classical links associated to each element of the second cohomology of a finite quandle. We study these invariants for Alexander quandles of the form Z[t,t^{-1}]/(p,…

Geometric Topology · Mathematics 2007-05-23 Richard A. Litherland

Racks and quandles are rich algebraic structures that are strong enough to classify knots. Here we develop several fundamental categorical aspects of the theories of racks and quandles and their relation to the theory of permutations. In…

Geometric Topology · Mathematics 2018-04-30 Markus Szymik

We consider involutory virtual biracks with good involutions, also known as symmetric involutory virtual biracks. Any good involution on an involutory virtual birack defines an enhancement of the counting invariant. We provide examples…

Geometric Topology · Mathematics 2017-09-12 Melinda Ho , Sam Nelson

A rack of order $n$ is a binary operation $\rack$ on a set $X$ of cardinality $n$, such that right multiplication is an automorphism. More precisely, $(X,\rack)$ is a rack provided that the map $x\mapsto x\rack y$ is a bijection for all…

Geometric Topology · Mathematics 2012-03-30 Simon R. Blackburn

Ribbon tangles are proper embeddings of tori and cylinders in the $4$-ball~$B^4$, "bounding" $3$-manifolds with only ribbon disks as singularities. We construct an Alexander invariant $\mathsf{A}$ of ribbon tangles equipped with a…

Geometric Topology · Mathematics 2016-02-22 Celeste Damiani , Vincent Florens

We introduce a new class of quantum enhancements we call biquandle brackets, which are customized skein invariants for biquandle colored links.Quantum enhancements of biquandle counting invariants form a class of knot and link invariants…

Geometric Topology · Mathematics 2017-02-17 Sam Nelson , Michael E. Orrison , Veronica Rivera

We introduce a six-variable polynomial invariant of Niebrzydowski tribrackets analogous to quandle,rack and biquandle polynomials. Using the subtribrackets of a tribracket, we additionally define subtribracket polynomials and establish a…

Geometric Topology · Mathematics 2021-03-05 Sam Nelson , Fletcher Nickerson

We introduce a new invariant of tangles along with an algebraic framework in which to understand it. We claim that the invariant contains the classical Alexander polynomial of knots and its multivariable extension to links. We argue that of…

Quantum Algebra · Mathematics 2013-09-16 Dror Bar-Natan , Sam Selmani

We enhance the tribracket counting invariant with \textit{tribracket brackets}, skein invariants of tribracket-colored oriented knots and links analogously to biquandle brackets. This infinite family of invariants includes the classical…

Geometric Topology · Mathematics 2023-11-21 Laira Aggarwal , Sam Nelson , Patricia Rivera

We introduce the notion of mc-biquandles, algebraic structures which have possibly distinct biquandle operations at single-component and multi-component crossings. These structures provide computable homset invariants for classical and…

Geometric Topology · Mathematics 2024-07-02 Seonmi Choi , Sam Nelson

In the paper we introduce a general approach how for a given virtual biquandle multi-switch $(S,V)$ on an algebraic system $X$ (from some category) and a given virtual link $L$ construct an algebraic system $X_{S,V}(L)$ (from the same…

Algebraic Topology · Mathematics 2020-01-22 Valeriy Bardakov , Timur Nasybullov

Marked vertex diagrams provide a combinatorial way to represent knotted surfaces in $\mathbb{R}^4$; including virtual crossings allows for a theory of virtual knotted surfaces and virtual cobordisms. Biquandle counting invariants are…

Geometric Topology · Mathematics 2015-06-08 Sam Nelson , Patricia Rivera

A tangle is an oriented 1-submanifold of the cylinder whose endpoints lie on the two disks in the boundary of the cylinder. Using an algebraic tool developed by Lescop, we extend the Burau representation of braids to a functor from the…

Geometric Topology · Mathematics 2014-07-29 Stephen Bigelow , Alessia Cattabriga , Vincent Florens

We introduce quiver representation-valued invariants of oriented virtual knots and links associated to a choice of finite virtual biquandle, abelian group, set of virtual Boltzmann weights, commutative unital ring and set of virtual…

Geometric Topology · Mathematics 2025-11-18 Alexander Bishop , Jose Ceniceros , Sam Nelson

The homology and cohomology of quandles and racks are used in knot theory: given a finite quandle and a cocycle, we can construct a knot invariant. This is a quick introductory survey to the invariants of knots derived from quandles and…

Geometric Topology · Mathematics 2007-05-23 Seiichi Kamada

In their paper entitled "Quantum Enhancements and Biquandle Brackets," Nelson, Orrison, and Rivera introduced biquandle brackets, which are customized skein invariants for biquandle-colored links. We prove herein that if a biquandle bracket…

Geometric Topology · Mathematics 2020-08-11 Will Hoffer , Adu Vengal , Vilas Winstein

We introduce \textit{Kaestner brackets}, a generalization of biquandle brackets to the case of parity biquandles. This infinite set of quantum enhancements of the biquandle counting invariant for oriented virtual knots and links includes…

Geometric Topology · Mathematics 2020-06-12 Forest Kobayashi , Sam Nelson

We define a new algebraic structure called a \emph{pointed rack} and use it to construct ambient isotopy invariants of $ n $-braids. We first introduce an integer-valued invariant of braids using pointed racks. This is then strengthened by…

Geometric Topology · Mathematics 2025-08-06 Angel Apollos , Jose Ceniceros