Table of Contents

Quandles

Abbreviation: Qnd

Definition

A \emph{quandle} is a structure $\mathbf{Q}=\langle Q,\triangleright,\triangleleft\rangle$ of type $\langle 2,2\rangle$ such that

$\triangleright$ is \emph{left-selfdistributive}: $x\triangleright(y\triangleright z)=(x\triangleright y)\triangleright(x\triangleright z)$

$\triangleleft$ is \emph{right-selfdistributive}: $(x\triangleleft y)\triangleleft z=(x\triangleleft z)\triangleleft(y\triangleleft z)$

$(x\triangleright y)\triangleleft x=y$

$x\triangleright (y\triangleleft x)=y$

$\triangleright$ is \emph{idempotent}: $x\triangleright x=x$

Remark: The last identity can equivalently be replaced by $\triangleleft$ is \emph{idempotent}: $x\triangleleft x=x$

Morphisms

Let $\mathbf{Q}$ and $\mathbf{R}$ be quandles. A morphism from $\mathbf{Q}$ to $\mathbf{R}$ is a function $h:Q\rightarrow R$ that is a homomorphism: $h(x \triangleright y)=h(x) \triangleright h(y)$ and $h(x \triangleleft y)=h(x) \triangleleft h(y)$.

Examples

Example 1: If $\langle G,\cdot,^{-1},1\rangle$ is a group and $x\triangleright y=xyx^{-1}$, $x\triangleleft y=x^{-1}yx$ (conjugation) then $\langle G,\triangleright,\triangleleft\rangle$ is a quandle.

Basic results

Properties

Feel free to add or delete properties from this list. The list below may contain properties that are not relevant to the class that is being described.

Finite members

$\begin{array}{lr}

f(1)= &1\\
f(2)= &1\\
f(3)= &3\\
f(4)= &7\\
f(5)= &22\\
f(6)= &73\\
f(7)= &298\\
f(8)= &1581\\
f(9)= &11079\\
f(10)= &\\

\end{array}$

Subclasses

Involutory quandles

Symmetric quandles

Abelian quandles

Superclasses

Racks

References