9_42 is Alexander Stoimenow's favourite knot!
Alsacian chair, alsacian museum, Strasbourg, France
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Knot presentations
Planar diagram presentation
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X1425 X5,10,6,11 X3948 X9,3,10,2 X16,12,17,11 X14,7,15,8 X6,15,7,16 X18,14,1,13 X12,18,13,17
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Gauss code
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-1, 4, -3, 1, -2, -7, 6, 3, -4, 2, 5, -9, 8, -6, 7, -5, 9, -8
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Dowker-Thistlethwaite code
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4 8 10 -14 2 -16 -18 -6 -12
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Conway Notation
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[22,3,2-]
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Minimum Braid Representative
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A Morse Link Presentation
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An Arc Presentation
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Length is 9, width is 4,
Braid index is 4
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![9 42 AP.gif](/images/6/69/9_42_AP.gif) [{11, 2}, {1, 9}, {10, 5}, {9, 11}, {8, 4}, {2, 7}, {6, 8}, {7, 10}, {5, 3}, {4, 1}, {3, 6}]
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[edit Notes on presentations of 9 42]
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A part of a knot and a part of a graph.
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Computer Talk
The above data is available with the
Mathematica package
KnotTheory`
. Your input (in
red) is realistic; all else should have the same content as in a real mathematica session, but with different formatting.
(The path below may be different on your system, and possibly also the KnotTheory` date)
In[1]:=
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AppendTo[$Path, "C:/drorbn/projects/KAtlas/"];
<< KnotTheory`
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In[3]:=
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K = Knot["9 42"];
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KnotTheory::loading: Loading precomputed data in PD4Knots`.
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Out[4]=
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X1425 X5,10,6,11 X3948 X9,3,10,2 X16,12,17,11 X14,7,15,8 X6,15,7,16 X18,14,1,13 X12,18,13,17
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Out[5]=
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-1, 4, -3, 1, -2, -7, 6, 3, -4, 2, 5, -9, 8, -6, 7, -5, 9, -8
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Out[6]=
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4 8 10 -14 2 -16 -18 -6 -12
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(The path below may be different on your system)
In[7]:=
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AppendTo[$Path, "C:/bin/LinKnot/"];
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In[8]:=
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ConwayNotation[K]
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KnotTheory::credits: The minimum braids representing the knots with up to 10 crossings were provided by Thomas Gittings. See arXiv:math.GT/0401051.
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Out[9]=
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In[10]:=
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{First[br], Crossings[br], BraidIndex[K]}
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KnotTheory::loading: Loading precomputed data in IndianaData`.
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In[11]:=
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Show[BraidPlot[br]]
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In[12]:=
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Show[DrawMorseLink[K]]
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KnotTheory::credits: "MorseLink was added to KnotTheory` by Siddarth Sankaran at the University of Toronto in the summer of 2005."
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KnotTheory::credits: "DrawMorseLink was written by Siddarth Sankaran at the University of Toronto in the summer of 2005."
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In[13]:=
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ap = ArcPresentation[K]
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Out[13]=
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ArcPresentation[{11, 2}, {1, 9}, {10, 5}, {9, 11}, {8, 4}, {2, 7}, {6, 8}, {7, 10}, {5, 3}, {4, 1}, {3, 6}]
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Four dimensional invariants
Polynomial invariants
Alexander polynomial |
![{\displaystyle -t^{2}+2t-1+2t^{-1}-t^{-2}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/4af699bcd4430b8ae8bd02450626982ca3d60a4e) |
Conway polynomial |
![{\displaystyle -z^{4}-2z^{2}+1}](https://wikimedia.org/api/rest_v1/media/math/render/svg/f4575f3f0140c003634c4f4936320d433f34f66e) |
2nd Alexander ideal (db, data sources) |
![{\displaystyle \{1\}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/5acdcac635f883f8b4f0a01aa03b16b22f23b124) |
Determinant and Signature |
{ 7, 2 } |
Jones polynomial |
![{\displaystyle q^{3}-q^{2}+q-1+q^{-1}-q^{-2}+q^{-3}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/bf1459f85ac0984c18c4cbb358c98e3d030e0c3c) |
HOMFLY-PT polynomial (db, data sources) |
![{\displaystyle -z^{4}+a^{2}z^{2}+z^{2}a^{-2}-4z^{2}+2a^{2}+2a^{-2}-3}](https://wikimedia.org/api/rest_v1/media/math/render/svg/5a239d79de1f130e04d54f84de97f938a870e1c4) |
Kauffman polynomial (db, data sources) |
![{\displaystyle az^{7}+z^{7}a^{-1}+a^{2}z^{6}+z^{6}a^{-2}+2z^{6}-5az^{5}-5z^{5}a^{-1}-5a^{2}z^{4}-5z^{4}a^{-2}-10z^{4}+6az^{3}+6z^{3}a^{-1}+6a^{2}z^{2}+6z^{2}a^{-2}+12z^{2}-2az-2za^{-1}-2a^{2}-2a^{-2}-3}](https://wikimedia.org/api/rest_v1/media/math/render/svg/15552827d88e6d8faff33e57fc8e7c899d671e89) |
The A2 invariant |
![{\displaystyle q^{10}+q^{8}+q^{6}-q^{2}-1-q^{-2}+q^{-6}+q^{-8}+q^{-10}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/6828afe857356bc46c13b876bd2afd0db6ab2e4b) |
The G2 invariant |
![{\displaystyle q^{46}+q^{42}+2q^{32}+q^{26}+q^{24}+q^{22}+q^{20}-q^{18}+q^{16}+q^{14}-q^{12}+q^{10}-q^{8}-q^{4}-2q^{2}-1-q^{-2}-q^{-4}-2q^{-6}-q^{-8}-q^{-10}+q^{-12}-q^{-14}-q^{-16}+q^{-20}+q^{-22}+q^{-24}+q^{-26}+3q^{-30}+q^{-34}+q^{-36}+q^{-40}+q^{-46}-q^{-50}-q^{-54}+q^{-56}-q^{-60}+q^{-62}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/413fa9c5c93ae177d7ad50d345d560feea49b2f3) |
Further Quantum Invariants
Further quantum knot invariants for 9_42.
A1 Invariants.
Weight
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Invariant
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1
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2
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3
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4
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5
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A2 Invariants.
Weight
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Invariant
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1,0
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1,1
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2,0
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A3 Invariants.
Weight
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Invariant
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0,1,0
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1,0,0
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A4 Invariants.
Weight
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Invariant
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0,1,0,0
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1,0,0,0
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B2 Invariants.
Weight
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Invariant
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0,1
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1,0
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D4 Invariants.
Weight
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Invariant
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1,0,0,0
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G2 Invariants.
Weight
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Invariant
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1,0
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Computer Talk
The above data is available with the
Mathematica package
KnotTheory`
, as shown in the (simulated) Mathematica session below. Your input (in
red) is realistic; all else should have the same content as in a real mathematica session, but with different formatting. This Mathematica session is also available (albeit only for the knot
5_2) as the notebook
PolynomialInvariantsSession.nb.
(The path below may be different on your system, and possibly also the KnotTheory` date)
In[1]:=
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AppendTo[$Path, "C:/drorbn/projects/KAtlas/"];
<< KnotTheory`
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In[3]:=
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K = Knot["9 42"];
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KnotTheory::loading: Loading precomputed data in PD4Knots`.
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Out[4]=
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Out[5]=
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In[6]:=
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Alexander[K, 2][t]
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KnotTheory::credits: The program Alexander[K, r] to compute Alexander ideals was written by Jana Archibald at the University of Toronto in the summer of 2005.
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Out[6]=
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In[7]:=
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{KnotDet[K], KnotSignature[K]}
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KnotTheory::loading: Loading precomputed data in Jones4Knots`.
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Out[8]=
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In[9]:=
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HOMFLYPT[K][a, z]
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KnotTheory::credits: The HOMFLYPT program was written by Scott Morrison.
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Out[9]=
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In[10]:=
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Kauffman[K][a, z]
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KnotTheory::loading: Loading precomputed data in Kauffman4Knots`.
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Out[10]=
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"Similar" Knots (within the Atlas)
Same Alexander/Conway Polynomial:
{}
Same Jones Polynomial (up to mirroring,
):
{}
Computer Talk
The above data is available with the
Mathematica package
KnotTheory`
. Your input (in
red) is realistic; all else should have the same content as in a real mathematica session, but with different formatting.
(The path below may be different on your system, and possibly also the KnotTheory` date)
In[1]:=
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AppendTo[$Path, "C:/drorbn/projects/KAtlas/"];
<< KnotTheory`
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In[3]:=
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K = Knot["9 42"];
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In[4]:=
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{A = Alexander[K][t], J = Jones[K][q]}
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KnotTheory::loading: Loading precomputed data in PD4Knots`.
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KnotTheory::loading: Loading precomputed data in Jones4Knots`.
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Out[4]=
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{ , }
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In[5]:=
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DeleteCases[Select[AllKnots[], (A === Alexander[#][t]) &], K]
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KnotTheory::loading: Loading precomputed data in DTCode4KnotsTo11`.
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KnotTheory::credits: The GaussCode to PD conversion was written by Siddarth Sankaran at the University of Toronto in the summer of 2005.
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In[6]:=
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DeleteCases[
Select[
AllKnots[],
(J === Jones[#][q] || (J /. q -> 1/q) === Jones[#][q]) &
],
K
]
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KnotTheory::loading: Loading precomputed data in Jones4Knots11`.
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V2,1 through V6,9:
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V2,1
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V3,1
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V4,1
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V4,2
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V4,3
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V5,1
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V5,2
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V5,3
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V5,4
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V6,1
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V6,2
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V6,3
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V6,4
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V6,5
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V6,6
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V6,7
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V6,8
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V6,9
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V2,1 through V6,9 were provided by Petr Dunin-Barkowski <barkovs@itep.ru>, Andrey Smirnov <asmirnov@itep.ru>, and Alexei Sleptsov <sleptsov@itep.ru> and uploaded on October 2010 by User:Drorbn. Note that they are normalized differently than V2 and V3.
The coefficients of the monomials are shown, along with their alternating sums (fixed , alternation over ). The squares with yellow highlighting are those on the "critical diagonals", where or , where 2 is the signature of 9 42. Nonzero entries off the critical diagonals (if any exist) are highlighted in red.
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-4 | -3 | -2 | -1 | 0 | 1 | 2 | χ |
7 | | | | | | | 1 | 1 |
5 | | | | | | | | 0 |
3 | | | | | 1 | 1 | | 0 |
1 | | | | 1 | 1 | | | 0 |
-1 | | | | 1 | 1 | | | 0 |
-3 | | 1 | 1 | | | | | 0 |
-5 | | | | | | | | 0 |
-7 | 1 | | | | | | | 1 |
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The Coloured Jones Polynomials