L2a1

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L2a1

L4a1

Contents

Image:L2a1.gif
(Knotscape image)
See the full Thistlethwaite Link Table (up to 11 crossings).

Visit L2a1's page at Knotilus.

Visit L2a1's page at the original Knot Atlas.

L2a1 is also known as the "Hopf Link".

exapnded Kolam Two-hearts [1]
exapnded Kolam Two-hearts [1]
Are they forever linked? [2]
Are they forever linked? [2]

[edit] Link Presentations

[edit Notes on L2a1's Link Presentations]

Planar diagram presentation X4132 X2314
Gauss code {1, -2}, {2, -1}
A Braid Representative
Image:BraidPart3.gifImage:BraidPart3.gif
Image:BraidPart4.gifImage:BraidPart4.gif
A Morse Link Presentation Image:L2a1_ML.gif

[edit] 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 a3z−1zaaz−1 (db)
Kauffman polynomial za3 + a3z−1a2za + az−1 (db)

[edit] Khovanov Homology

The coefficients of the monomials trqj are shown, along with their alternating sums χ (fixed j, alternation over r). The squares with yellow highlighting are those on the "critical diagonals", where j−2r = s + 1 or j−2r = s−1, where s = -1 is the signature of L2a1. Nonzero entries off the critical diagonals (if any exist) are highlighted in red.    Data:L2a1/KhovanovTable
Integral Khovanov Homology

(db, data source)

  
\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}

[edit] Computer Talk

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

[edit] Modifying This Page

Read me first: Modifying Knot Pages

See/edit the Link Page master template (intermediate).

See/edit the Link_Splice_Base (expert).

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L2a1

L4a1

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