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Related papers: Birack modules and their link invariants

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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 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

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

We define invariants of unoriented knots and links by enhancing the integral kei counting invariant Phi_X^Z (K) for a finite kei X using representations of the kei algebra, Z_K[X], a quotient of the quandle algebra Z[X] defined by…

Geometric Topology · Mathematics 2011-02-23 Mike Grier , Sam Nelson

We introduce an algebra Z[X,S] associated to a pair (X,S) of a virtual birack X and X-shadow S. We use modules over Z[X,S] to define enhancements of the virtual birack shadow counting invariant, extending the birack shadow module invariants…

Geometric Topology · Mathematics 2012-04-20 Jackson Blankstein , Susan Kim , Catherine Lepel , Sam Nelson , Nicole Sanderson

A birack is an algebraic structure with axioms encoding the blackboard-framed Reidemeister moves, incorporating quandles, racks, strong biquandles and semiquandles as special cases. In this paper we extend the counting invariant for finite…

Geometric Topology · Mathematics 2010-12-23 Sam Nelson

We study Coxeter racks over $\mathbb{Z}_n$ and the knot and link invariants they define. We exploit the module structure of these racks to enhance the rack counting invariants and give examples showing that these enhanced invariants are…

Geometric Topology · Mathematics 2008-08-13 Sam Nelson , Ryan Wieghard

We introduce the notion of N-reduced dynamical cocycles and use these objects to define enhancements of the rack counting invariant for classical and virtual knots and links. We provide examples to show that the new invariants are not…

Geometric Topology · Mathematics 2011-08-23 Alissa S. Crans , Sam Nelson , Aparna Sarkar

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 enhance the biquandle counting invariant using elements of truncated biquandle-labeled Polyak algebras. These finite type enhancements reduce to the finite type enhancements defined by Goussarov, Polyak and Viro for the trivial biquandle…

Geometric Topology · Mathematics 2015-06-03 Sam Nelson

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

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

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

New definitions of rack and quandle modules are introduced, and shown to generalise the definitions previously studied by Andruskiewitsch, Etingof and Grana. This new construct is shown to coincide with Beck's general definition of a module…

Category Theory · Mathematics 2007-05-23 Nicholas Jackson

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 generalise the finite biquandle colouring invariant to a polynomial invariant based on labelling a knot diagram with a finite birack that reduces to the biquandle colouring invariant in that case. The polynomial is an invariant of a…

Geometric Topology · Mathematics 2025-03-12 Andrew Bartholomew , Roger Fenn , Louis Kauffman

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

A (t,s)-rack is a rack structure defined on a module over the ring $\ddot\Lambda=\mathbb{Z}[t^{\pm 1},s]/(s^2-(1-t)s)$. We identify necessary and sufficient conditions for two $(t,s)$-racks to be isomorphic. We define enhancements of the…

Geometric Topology · Mathematics 2011-05-06 Jessica Ceniceros , Sam Nelson

From the braid-valued Burau module over the braid group we construct the Yang-Baxter matrices yielding the Alexander- and the Jones knot invariants. This generalises an observation of V. F. R. Jones.

q-alg · Mathematics 2008-02-03 Florin Constantinescu , Mirko Luedde

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
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