4 1
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(KnotPlot image) |
See the full Rolfsen Knot Table. Visit 4 1's page at the Knot Server (KnotPlot driven, includes 3D interactive images!) |
4_1 is also known as "the Figure Eight knot", as some people think it looks like a figure `8' in one of its common projections. See e.g. [1] . For two 4_1 knots along a closed loop, see 10_59, 10_60, K12a975, and K12a991. |
Non-prime (compound) versions
Knot presentations
Planar diagram presentation | X4251 X8615 X6374 X2738 |
Gauss code | 1, -4, 3, -1, 2, -3, 4, -2 |
Dowker-Thistlethwaite code | 4 6 8 2 |
Conway Notation | [22] |
Minimum Braid Representative | A Morse Link Presentation | An Arc Presentation | |||
Length is 4, width is 3, Braid index is 3 |
[{3, 5}, {6, 4}, {5, 2}, {1, 3}, {2, 6}, {4, 1}] |
[edit Notes on presentations of 4 1]
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[$Path, "C:/drorbn/projects/KAtlas/"];
<< KnotTheory`
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Loading KnotTheory` version of May 31, 2006, 14:15:20.091.
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In[3]:=
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K = Knot["4 1"];
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In[4]:=
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PD[K]
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KnotTheory::loading: Loading precomputed data in PD4Knots`.
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Out[4]=
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X4251 X8615 X6374 X2738 |
In[5]:=
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GaussCode[K]
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Out[5]=
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1, -4, 3, -1, 2, -3, 4, -2 |
In[6]:=
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DTCode[K]
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Out[6]=
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4 6 8 2 |
(The path below may be different on your system)
In[7]:=
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AppendTo[$Path, "C:/bin/LinKnot/"];
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In[8]:=
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ConwayNotation[K]
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Out[8]=
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[22] |
In[9]:=
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br = BR[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::credits: The braid index data known to KnotTheory` is taken from Charles Livingston's http://www.indiana.edu/~knotinfo/.
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KnotTheory::loading: Loading precomputed data in IndianaData`.
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Out[10]=
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{ 3, 4, 3 } |
In[11]:=
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Show[BraidPlot[br]]
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Out[11]=
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-Graphics- |
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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Out[12]=
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-Graphics- |
In[13]:=
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ap = ArcPresentation[K]
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Out[13]=
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ArcPresentation[{3, 5}, {6, 4}, {5, 2}, {1, 3}, {2, 6}, {4, 1}] |
In[14]:=
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Draw[ap]
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Out[14]=
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-Graphics- |
Three dimensional invariants
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Four dimensional invariants
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Polynomial invariants
A1 Invariants.
Weight | Invariant |
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1 | |
2 | |
3 | |
4 | |
5 | |
6 |
A2 Invariants.
Weight | Invariant |
---|---|
1,0 | |
1,1 | |
2,0 | |
3,0 |
A3 Invariants.
Weight | Invariant |
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0,1,0 | |
1,0,0 | |
1,0,1 |
A4 Invariants.
Weight | Invariant |
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0,1,0,0 | |
1,0,0,0 |
B2 Invariants.
Weight | Invariant |
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0,1 | |
1,0 |
B3 Invariants.
Weight | Invariant |
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1,0,0 |
B4 Invariants.
Weight | Invariant |
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1,0,0,0 |
C3 Invariants.
Weight | Invariant |
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1,0,0 |
C4 Invariants.
Weight | Invariant |
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1,0,0,0 |
D4 Invariants.
Weight | Invariant |
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0,1,0,0 | |
1,0,0,0 |
G2 Invariants.
Weight | Invariant |
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1,0 |
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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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Loading KnotTheory` version of August 31, 2006, 11:25:27.5625.
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In[3]:=
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K = Knot["4 1"];
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In[4]:=
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Alexander[K][t]
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KnotTheory::loading: Loading precomputed data in PD4Knots`.
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Out[4]=
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In[5]:=
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Conway[K][z]
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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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Out[7]=
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{ 5, 0 } |
In[8]:=
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Jones[K][q]
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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, ): {K11n19,}
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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Loading KnotTheory` version of May 31, 2006, 14:15:20.091.
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In[3]:=
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K = Knot["4 1"];
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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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{ , } |
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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Out[5]=
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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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Out[6]=
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{K11n19,} |
Vassiliev invariants
V2 and V3: | (-1, 0) |
V2,1 through 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.
Khovanov Homology
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 0 is the signature of 4 1. Nonzero entries off the critical diagonals (if any exist) are highlighted in red. |
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Integral Khovanov Homology
(db, data source) |
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The Coloured Jones Polynomials
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n} | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle J_n} |
2 | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle q^6-q^5-q^4+2 q^3-q^2-q+3- q^{-1} - q^{-2} +2 q^{-3} - q^{-4} - q^{-5} + q^{-6} } |
3 | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle q^{12}-q^{11}-q^{10}+2 q^8-2 q^6+3 q^4-3 q^2+3-3 q^{-2} +3 q^{-4} -2 q^{-6} +2 q^{-8} - q^{-10} - q^{-11} + q^{-12} } |
4 | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle q^{20}-q^{19}-q^{18}+3 q^{15}-q^{14}-q^{13}-q^{12}-q^{11}+5 q^{10}-q^9-2 q^8-2 q^7-q^6+6 q^5-q^4-2 q^3-2 q^2-q+7- q^{-1} -2 q^{-2} -2 q^{-3} - q^{-4} +6 q^{-5} - q^{-6} -2 q^{-7} -2 q^{-8} - q^{-9} +5 q^{-10} - q^{-11} - q^{-12} - q^{-13} - q^{-14} +3 q^{-15} - q^{-18} - q^{-19} + q^{-20} } |
5 | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle q^{30}-q^{29}-q^{28}+q^{25}+2 q^{24}-2 q^{22}-q^{21}-q^{20}+q^{19}+3 q^{18}+q^{17}-2 q^{16}-3 q^{15}-2 q^{14}+2 q^{13}+4 q^{12}+2 q^{11}-2 q^{10}-4 q^9-2 q^8+2 q^7+5 q^6+2 q^5-2 q^4-5 q^3-2 q^2+2 q+5+2 q^{-1} -2 q^{-2} -5 q^{-3} -2 q^{-4} +2 q^{-5} +5 q^{-6} +2 q^{-7} -2 q^{-8} -4 q^{-9} -2 q^{-10} +2 q^{-11} +4 q^{-12} +2 q^{-13} -2 q^{-14} -3 q^{-15} -2 q^{-16} + q^{-17} +3 q^{-18} + q^{-19} - q^{-20} - q^{-21} -2 q^{-22} +2 q^{-24} + q^{-25} - q^{-28} - q^{-29} + q^{-30} } |
6 | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle q^{42}-q^{41}-q^{40}+q^{37}+3 q^{35}-q^{34}-2 q^{33}-q^{32}-q^{31}+6 q^{28}-q^{27}-2 q^{26}-2 q^{25}-2 q^{24}-q^{23}+9 q^{21}-2 q^{19}-3 q^{18}-3 q^{17}-2 q^{16}+11 q^{14}-2 q^{12}-4 q^{11}-4 q^{10}-2 q^9+12 q^7-2 q^5-4 q^4-4 q^3-2 q^2+13-2 q^{-2} -4 q^{-3} -4 q^{-4} -2 q^{-5} +12 q^{-7} -2 q^{-9} -4 q^{-10} -4 q^{-11} -2 q^{-12} +11 q^{-14} -2 q^{-16} -3 q^{-17} -3 q^{-18} -2 q^{-19} +9 q^{-21} - q^{-23} -2 q^{-24} -2 q^{-25} -2 q^{-26} - q^{-27} +6 q^{-28} - q^{-31} - q^{-32} -2 q^{-33} - q^{-34} +3 q^{-35} + q^{-37} - q^{-40} - q^{-41} + q^{-42} } |
7 | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle q^{56}-q^{55}-q^{54}+q^{51}+q^{49}+2 q^{48}-q^{47}-2 q^{46}-q^{45}-2 q^{44}+q^{43}+q^{41}+5 q^{40}-2 q^{38}-2 q^{37}-4 q^{36}+2 q^{33}+7 q^{32}+q^{31}-q^{30}-2 q^{29}-7 q^{28}-2 q^{27}+2 q^{25}+9 q^{24}+2 q^{23}-3 q^{21}-9 q^{20}-3 q^{19}+3 q^{17}+10 q^{16}+3 q^{15}-3 q^{13}-10 q^{12}-3 q^{11}+3 q^9+11 q^8+3 q^7-3 q^5-11 q^4-3 q^3+3 q+11+3 q^{-1} -3 q^{-3} -11 q^{-4} -3 q^{-5} +3 q^{-7} +11 q^{-8} +3 q^{-9} -3 q^{-11} -10 q^{-12} -3 q^{-13} +3 q^{-15} +10 q^{-16} +3 q^{-17} -3 q^{-19} -9 q^{-20} -3 q^{-21} +2 q^{-23} +9 q^{-24} +2 q^{-25} -2 q^{-27} -7 q^{-28} -2 q^{-29} - q^{-30} + q^{-31} +7 q^{-32} +2 q^{-33} -4 q^{-36} -2 q^{-37} -2 q^{-38} +5 q^{-40} + q^{-41} + q^{-43} -2 q^{-44} - q^{-45} -2 q^{-46} - q^{-47} +2 q^{-48} + q^{-49} + q^{-51} - q^{-54} - q^{-55} + q^{-56} } |
Computer Talk
Much of the above data can be recomputed by Mathematica using the package KnotTheory`
. See A Sample KnotTheory` Session, or any of the Computer Talk sections above.
Modifying This Page
Read me first: Modifying Knot Pages
See/edit the Rolfsen Knot Page master template (intermediate). See/edit the Rolfsen_Splice_Base (expert). Back to the top. |
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