7 4
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Visit 7 4's page at the Knot Server (KnotPlot driven, includes 3D interactive images!)
Visit 7 4's page at Knotilus! Visit 7 4's page at the original Knot Atlas! Simplest version of Endless knot symbol. |
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Knot presentations
Planar diagram presentation | X6271 X12,6,13,5 X14,8,1,7 X8,14,9,13 X2,12,3,11 X10,4,11,3 X4,10,5,9 |
Gauss code | 1, -5, 6, -7, 2, -1, 3, -4, 7, -6, 5, -2, 4, -3 |
Dowker-Thistlethwaite code | 6 10 12 14 4 2 8 |
Conway Notation | [313] |
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 |
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1,0 | |
1,1 | |
2,0 | |
3,0 |
A3 Invariants.
Weight | Invariant |
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0,1,0 | |
1,0,0 |
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 |
D4 Invariants.
Weight | Invariant |
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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["7 4"];
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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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{ 15, 2 } |
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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Vassiliev invariants
V2 and V3: | (4, 8) |
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 2 is the signature of 7 4. 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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Computer Talk
Much of the above data can be recomputed by Mathematica using the package KnotTheory`
. See A Sample KnotTheory` Session.
In[1]:= |
<< KnotTheory` |
Loading KnotTheory` (version of August 17, 2005, 14:44:34)... | |
In[2]:= | Crossings[Knot[7, 4]] |
Out[2]= | 7 |
In[3]:= | PD[Knot[7, 4]] |
Out[3]= | PD[X[6, 2, 7, 1], X[12, 6, 13, 5], X[14, 8, 1, 7], X[8, 14, 9, 13], X[2, 12, 3, 11], X[10, 4, 11, 3], X[4, 10, 5, 9]] |
In[4]:= | GaussCode[Knot[7, 4]] |
Out[4]= | GaussCode[1, -5, 6, -7, 2, -1, 3, -4, 7, -6, 5, -2, 4, -3] |
In[5]:= | BR[Knot[7, 4]] |
Out[5]= | BR[4, {1, 1, 2, -1, 2, 2, 3, -2, 3}] |
In[6]:= | alex = Alexander[Knot[7, 4]][t] |
Out[6]= | 4 |
In[7]:= | Conway[Knot[7, 4]][z] |
Out[7]= | 2 1 + 4 z |
In[8]:= | Select[AllKnots[], (alex === Alexander[#][t])&] |
Out[8]= | {Knot[7, 4], Knot[9, 2]} |
In[9]:= | {KnotDet[Knot[7, 4]], KnotSignature[Knot[7, 4]]} |
Out[9]= | {15, 2} |
In[10]:= | J=Jones[Knot[7, 4]][q] |
Out[10]= | 2 3 4 5 6 7 8 q - 2 q + 3 q - 2 q + 3 q - 2 q + q - q |
In[11]:= | Select[AllKnots[], (J === Jones[#][q] || (J /. q-> 1/q) === Jones[#][q])&] |
Out[11]= | {Knot[7, 4]} |
In[12]:= | A2Invariant[Knot[7, 4]][q] |
Out[12]= | 2 4 8 10 12 14 16 20 24 26 q - q + q + q + 2 q + q + q - q - q - q |
In[13]:= | Kauffman[Knot[7, 4]][a, z] |
Out[13]= | 2 2 2 2 3 3 3-8 2 4 z 4 z 2 z 3 z 4 z z 4 z 8 z 2 z |
In[14]:= | {Vassiliev[2][Knot[7, 4]], Vassiliev[3][Knot[7, 4]]} |
Out[14]= | {0, 8} |
In[15]:= | Kh[Knot[7, 4]][q, t] |
Out[15]= | 3 3 5 2 7 2 7 3 9 3 9 4 11 4 |