L2a1

 L2a1
 (Knotscape image) See the full Thistlethwaite Link Table (up to 11 crossings). Visit L2a1 at Knotilus! L2a1 is $2^2_1$ in Rolfsen's table of links. It is also known as the "Hopf Link".

 Japanese family emblem Linked hearts expanded Kolam Two-hearts [1] Logo In Star of David form on old Jewish building in Prague Three wreaths linked as two L2a1 configurations on Michelangelo's tomb One form of a heterosexuality symbol (pseudo-3D) Are they forever linked? [2] As impossible object Linked hearts (pseudo-3D) German coat of arms

 Planar diagram presentation X4132 X2314 Gauss code {1, -2}, {2, -1}

Polynomial invariants

 Multivariable Alexander Polynomial (in $u$, $v$, $w$, ...) $-1$ (db) Jones polynomial $-\frac{1}{\sqrt{q}}-\frac{1}{q^{5/2}}$ (db) Signature -1 (db) HOMFLY-PT polynomial $a^3 z^{-1} -z a-a z^{-1}$ (db) Kauffman polynomial $-z a^3+a^3 z^{-1} -a^2-z a+a z^{-1}$ (db)

Khovanov Homology

The coefficients of the monomials $t^rq^j$ are shown, along with their alternating sums $\chi$ (fixed $j$, alternation over $r$).
 \ r \ j \
-2-10χ
0  11
-2  11
-41  1
-61  1
Integral Khovanov Homology
 $\dim{\mathcal G}_{2r+i}\operatorname{KH}^r_{\mathbb Z}$ $i=-2$ $i=0$ $r=-2$ ${\mathbb Z}$ ${\mathbb Z}$ $r=-1$ $r=0$ ${\mathbb Z}$ ${\mathbb Z}$

Computer Talk

Much of the above data can be recomputed by Mathematica using the package KnotTheory. See A Sample KnotTheory Session.