T(7,2)
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Visit [[[:Template:KnotilusURL]] T(7,2)'s page] at Knotilus!
Visit T(7,2)'s page at the original Knot Atlas! |
| See also 7_1. |
T(7,2) Further Notes and Views
Knot presentations
| Planar diagram presentation | X5,13,6,12 X13,7,14,6 X7,1,8,14 X1928 X9,3,10,2 X3,11,4,10 X11,5,12,4 |
| Gauss code | -4, 5, -6, 7, -1, 2, -3, 4, -5, 6, -7, 1, -2, 3 |
| Dowker-Thistlethwaite code | 8 10 12 14 2 4 6 |
| Conway Notation | Data:T(7,2)/Conway Notation |
Polynomial invariants
| Alexander polynomial | 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 t^3-t^2+t-1+ t^{-1} - t^{-2} + t^{-3} } |
| Conway polynomial | 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 z^6+5 z^4+6 z^2+1} |
| 2nd Alexander ideal (db, data sources) | 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 \{1\}} |
| Determinant and Signature | { 7, 6 } |
| Jones polynomial | 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^{10}+q^9-q^8+q^7-q^6+q^5+q^3} |
| HOMFLY-PT polynomial (db, data sources) | 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 z^6 a^{-6} +6 z^4 a^{-6} -z^4 a^{-8} +10 z^2 a^{-6} -4 z^2 a^{-8} +4 a^{-6} -3 a^{-8} } |
| Kauffman polynomial (db, data sources) | 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 z^6 a^{-6} +z^6 a^{-8} +z^5 a^{-7} +z^5 a^{-9} -6 z^4 a^{-6} -5 z^4 a^{-8} +z^4 a^{-10} -4 z^3 a^{-7} -3 z^3 a^{-9} +z^3 a^{-11} +10 z^2 a^{-6} +7 z^2 a^{-8} -2 z^2 a^{-10} +z^2 a^{-12} +3 z a^{-7} +z a^{-9} -z a^{-11} +z a^{-13} -4 a^{-6} -3 a^{-8} } |
| The A2 invariant | Data:T(7,2)/QuantumInvariant/A2/1,0 |
| The G2 invariant | Data:T(7,2)/QuantumInvariant/G2/1,0 |
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["T(7,2)"];
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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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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 t^3-t^2+t-1+ t^{-1} - t^{-2} + t^{-3} } |
In[5]:=
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Conway[K][z]
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Out[5]=
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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 z^6+5 z^4+6 z^2+1} |
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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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 \{1\}} |
In[7]:=
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{KnotDet[K], KnotSignature[K]}
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Out[7]=
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{ 7, 6 } |
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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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^{10}+q^9-q^8+q^7-q^6+q^5+q^3} |
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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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 z^6 a^{-6} +6 z^4 a^{-6} -z^4 a^{-8} +10 z^2 a^{-6} -4 z^2 a^{-8} +4 a^{-6} -3 a^{-8} } |
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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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 z^6 a^{-6} +z^6 a^{-8} +z^5 a^{-7} +z^5 a^{-9} -6 z^4 a^{-6} -5 z^4 a^{-8} +z^4 a^{-10} -4 z^3 a^{-7} -3 z^3 a^{-9} +z^3 a^{-11} +10 z^2 a^{-6} +7 z^2 a^{-8} -2 z^2 a^{-10} +z^2 a^{-12} +3 z a^{-7} +z a^{-9} -z a^{-11} +z a^{-13} -4 a^{-6} -3 a^{-8} } |
Vassiliev invariants
| V2 and V3: | (6, 14) |
| 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 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 t^rq^j} are shown, along with their alternating sums 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 \chi} (fixed , alternation over ). The squares with yellow highlighting are those on the "critical diagonals", where 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-2r=s+1} or 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-2r=s-1} , where 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 s=} 6 is the signature of T(7,2). 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.
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 \textrm{Include}(\textrm{ColouredJonesM.mhtml})}
In[1]:= |
<< KnotTheory` |
Loading KnotTheory` (version of August 17, 2005, 14:44:34)... | |
In[2]:= | Crossings[TorusKnot[7, 2]] |
Out[2]= | 7 |
In[3]:= | PD[TorusKnot[7, 2]] |
Out[3]= | PD[X[5, 13, 6, 12], X[13, 7, 14, 6], X[7, 1, 8, 14], X[1, 9, 2, 8], X[9, 3, 10, 2], X[3, 11, 4, 10], X[11, 5, 12, 4]] |
In[4]:= | GaussCode[TorusKnot[7, 2]] |
Out[4]= | GaussCode[-4, 5, -6, 7, -1, 2, -3, 4, -5, 6, -7, 1, -2, 3] |
In[5]:= | BR[TorusKnot[7, 2]] |
Out[5]= | BR[2, {1, 1, 1, 1, 1, 1, 1}] |
In[6]:= | alex = Alexander[TorusKnot[7, 2]][t] |
Out[6]= | -3 -2 1 |
In[7]:= | Conway[TorusKnot[7, 2]][z] |
Out[7]= | 2 4 6 1 + 6 z + 5 z + z |
In[8]:= | Select[AllKnots[], (alex === Alexander[#][t])&] |
Out[8]= | {Knot[7, 1]} |
In[9]:= | {KnotDet[TorusKnot[7, 2]], KnotSignature[TorusKnot[7, 2]]} |
Out[9]= | {7, 6} |
In[10]:= | J=Jones[TorusKnot[7, 2]][q] |
Out[10]= | 3 5 6 7 8 9 10 q + q - q + q - q + q - q |
In[11]:= | Select[AllKnots[], (J === Jones[#][q] || (J /. q-> 1/q) === Jones[#][q])&] |
Out[11]= | {Knot[7, 1]} |
In[12]:= | A2Invariant[TorusKnot[7, 2]][q] |
Out[12]= | 10 12 14 16 18 26 28 30 q + q + 2 q + q + q - q - q - q |
In[13]:= | Kauffman[TorusKnot[7, 2]][a, z] |
Out[13]= | 2 2 2 2 3 |
In[14]:= | {Vassiliev[2][TorusKnot[7, 2]], Vassiliev[3][TorusKnot[7, 2]]} |
Out[14]= | {0, 14} |
In[15]:= | Kh[TorusKnot[7, 2]][q, t] |
Out[15]= | 5 7 2 9 3 13 4 13 |


