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Related papers: Link invariants from finite biracks

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Biracks are algebraic structures related to knots and links. We define a new enhancement of the birack counting invariant for oriented classical and virtual knots and links via algebraic structures called birack dynamical cocycles. The new…

Geometric Topology · Mathematics 2012-05-22 Sam Nelson , Emily Watterberg

We identify a subcategory of biracks which define counting invariants of unoriented links, which we call involutory biracks. In particular, involutory biracks of birack rank N=1 are biquandles, which we call bikei. We define counting…

Geometric Topology · Mathematics 2011-04-25 Sinan Aksoy , Sam Nelson

We consider birack and switch colorings of braids. We define a switch structure on the set of permutation representations of the braid group and consider when such a representation is a switch automorphism. We define quiver-valued…

Geometric Topology · Mathematics 2024-07-02 Max Chao-Haft , Sam Nelson

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

Birack modules are modules over an algebra Z[X] associated to a finite birack X. In previous work, birack module structures on Z mod n were used to enhance the birack counting invariant. In this paper, we use birack modules over Laurent…

Geometric Topology · Mathematics 2014-06-12 Evan Cody , Sam Nelson

We define an invariant of tangles and framed tangles given a finite crossed module and a pair of functions, called a Reidemeister pair, satisfying natural properties. We give several examples of Reidemeister pairs derived from racks,…

Geometric Topology · Mathematics 2013-01-28 João Faria Martins , Roger Picken

We define an invariant of tangles and framed tangles given a finite crossed module and a pair of functions, called a Reidemeister pair, satisfying natural properties. We give several examples of Reidemeister pairs derived from racks,…

Geometric Topology · Mathematics 2017-05-23 Joao Faria Martins , Roger Picken

We extend the rack algebra Z[X] defined by Andruskiewitsch and Grana to the case of biracks, enabling a notion of birack modules. We use these birack modules to define an enhancement of the birack counting invariant generalizing the birack…

Geometric Topology · Mathematics 2012-12-14 Regina Bauernschmidt , Sam Nelson

The involutory birack counting invariant is an integer-valued invariant of unoriented tangles defined by counting homomorphisms from the fundamental involutory birack of the tangle to a finite involutory birack over a set of framings modulo…

Geometric Topology · Mathematics 2014-03-18 Sam Nelson , Veronica Rivera

We define ambient isotopy invariants of oriented knots and links using the counting invariants of framed links defined by finite racks. These invariants reduce to the usual quandle counting invariant when the rack in question is a quandle.…

Geometric Topology · Mathematics 2013-07-30 Sam Nelson

A virtual link can be understood as a link in a trivial I-bundle over an orientable compact surface with genus. A twisted virtual link is a link in a trivial I-bundle over a not-necessarily orientable compact surface. A twisted virtual…

Geometric Topology · Mathematics 2012-12-03 Jessica Ceniceros , Sam Nelson

We introduce an associative algebra Z[X,S] associated to a birack shadow and define enhancements of the birack counting invariant for classical knots and links via representations of Z[X,S] known as shadow modules. We provide examples which…

Geometric Topology · Mathematics 2011-06-03 Sam Nelson , Katie Pelland

In this paper, we introduce biquandle power brackets, an infinite family of invariants of oriented links containing the classical skein invariants and the quandle and biquandle 2-cocycle invariants as special cases. Biquandle power brackets…

Geometric Topology · Mathematics 2024-01-23 Neslihan Gügümcü , Sam Nelson

We study rack polynomials and the link invariants they define. We show that constant action racks are classified by their generalized rack polynomials and show that $ns^at^a$-quandles are not classified by their generalized quandle…

Geometric Topology · Mathematics 2019-03-13 Tim Carrell , Sam Nelson

We introduce birack brackets, skein invariants of birack-colored framed classical and virtual knots and links with values in a commutative unital ring. The multiset of birack bracket values over the homset from a framed link's fundamental…

Geometric Topology · Mathematics 2026-02-09 Sam Nelson , Haoqi Tom Tang

In this paper we give the results of a computer search for biracks of small size and we give various interpretations of these findings. The list includes biquandles, racks and quandles together with new invariants of welded knots and…

Geometric Topology · Mathematics 2010-04-09 Andrew Bartholomew , Roger Fenn

We restructure and advance the classification theory of finite racks and quandles by employing powerful methods from transformation groups and representation theory, especially Burnside rings. These rings serve as universal receptacles for…

Representation Theory · Mathematics 2025-07-03 Nadia Mazza , Markus Szymik

We introduce a modified rack algebra Z[X] for racks X with finite rack rank N. We use representations of Z[X] into rings, known as rack modules, to define enhancements of the rack counting invariant for classical and virtual knots and…

Geometric Topology · Mathematics 2010-08-04 Aaron Haas , Garret Heckel , Sam Nelson , Jonah Yuen , Qingcheng Zhang

In this paper we give the results of a computer search for biracks of small size and we give various interpretations of these findings. The list includes biquandles, racks and quandles together with new invariants of welded knots and…

Geometric Topology · Mathematics 2010-01-29 Andrew Bartholomew , Roger Fenn

We study the quandle counting invariant for a certain family of finite quandles with trivial orbit subquandles. We show how these invariants determine the linking number of classical two-component links up to sign.

Geometric Topology · Mathematics 2008-08-13 Natasha Harrell , Sam Nelson
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