© | Dror Bar-Natan: The Knot Atlas: The Rolfsen Knot Table: |
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The Alternating Knot 81Visit 81's page at the Knot Server (KnotPlot driven, includes 3D interactive images!) |
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PD Presentation: | X1425 X9,12,10,13 X3,11,4,10 X11,3,12,2 X5,16,6,1 X7,14,8,15 X13,8,14,9 X15,6,16,7 |
Gauss Code: | {-1, 4, -3, 1, -5, 8, -6, 7, -2, 3, -4, 2, -7, 6, -8, 5} |
DT (Dowker-Thistlethwaite) Code: | 4 10 16 14 12 2 8 6 |
Minimum Braid Representative:
Length is 10, width is 5 Braid index is 5 |
A Morse Link Presentation:
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3D Invariants: |
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Alexander Polynomial: | - 3t-1 + 7 - 3t |
Conway Polynomial: | 1 - 3z2 |
Other knots with the same Alexander/Conway Polynomial: | {...} |
Determinant and Signature: | {13, 0} |
Jones Polynomial: | q-6 - q-5 + q-4 - 2q-3 + 2q-2 - 2q-1 + 2 - q + q2 |
Other knots (up to mirrors) with the same Jones Polynomial: | {K11n70, ...} |
A2 (sl(3)) Invariant: | q-20 + q-18 - q-12 - q-10 + q2 + q6 + q8 |
HOMFLY-PT Polynomial: | a-2 - z2 - a2z2 - a4 - a4z2 + a6 |
Kauffman Polynomial: | - a-2 + a-2z2 + a-1z3 + z4 - az3 + az5 - 2a2z4 + a2z6 - 3a3z + 5a3z3 - 4a3z5 + a3z7 - a4 + 7a4z2 - 8a4z4 + 2a4z6 - 3a5z + 7a5z3 - 5a5z5 + a5z7 - a6 + 6a6z2 - 5a6z4 + a6z6 |
V2 and V3, the type 2 and 3 Vassiliev invariants: | {-3, 3} |
Khovanov Homology:
(The squares with yellow highlighting are those on the "critical diagonals", where j-2r=s+1 or j-2r=s+1, where s=0 is the signature of 81. Nonzero entries off the critical diagonals (if any exist) are highlighted in red.) |
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n | Coloured Jones Polynomial (in the (n+1)-dimensional representation of sl(2)) |
2 | q-18 - q-17 - q-16 + 2q-15 - q-14 - 2q-13 + 3q-12 - 3q-10 + 3q-9 - 3q-7 + 3q-6 + q-5 - 3q-4 + 2q-3 + q-2 - 3q-1 + 2 - 2q2 + 2q3 - q5 + q6 |
3 | q-36 - q-35 - q-34 + 2q-32 - 2q-30 - q-29 + 3q-28 + q-27 - 2q-26 - 2q-25 + 2q-24 + 2q-23 - 2q-22 - 2q-21 + 2q-20 + 2q-19 - 2q-18 - q-17 + 2q-16 + q-15 - 3q-14 + 2q-12 - 3q-10 + q-9 + 2q-8 - q-7 - 2q-6 + 2q-5 + 3q-4 - 2q-3 - 2q-2 + 4 - q - 2q2 - q3 + 3q4 - q6 - 2q7 + 2q8 - q11 + q12 |
4 | q-60 - q-59 - q-58 + 3q-55 - q-54 - q-53 - q-52 - 2q-51 + 5q-50 - q-48 - q-47 - 4q-46 + 5q-45 - 5q-41 + 5q-40 - 5q-36 + 6q-35 - q-33 - q-32 - 6q-31 + 8q-30 + q-29 - 2q-28 - 2q-27 - 7q-26 + 10q-25 + 3q-24 - 3q-23 - 3q-22 - 8q-21 + 11q-20 + 5q-19 - 4q-18 - 4q-17 - 8q-16 + 11q-15 + 6q-14 - 5q-13 - 5q-12 - 8q-11 + 12q-10 + 7q-9 - 6q-8 - 6q-7 - 8q-6 + 12q-5 + 7q-4 - 4q-3 - 5q-2 - 9q-1 + 10 + 6q - 2q2 - 3q3 - 7q4 + 7q5 + 3q6 - q7 - q8 - 5q9 + 4q10 + q11 - 3q14 + 2q15 - q19 + q20 |
5 | q-90 - q-89 - q-88 + q-85 + 2q-84 - 2q-82 - q-81 - q-80 + 3q-78 + 2q-77 - q-76 - 2q-75 - 2q-74 - q-73 + 2q-72 + 3q-71 - q-69 - 2q-68 - q-67 + q-66 + 2q-65 + q-64 - q-63 - 2q-62 - q-61 + q-60 + 3q-59 + q-58 - 2q-57 - 3q-56 - 2q-55 + q-54 + 5q-53 + 3q-52 - 2q-51 - 5q-50 - 4q-49 + q-48 + 6q-47 + 6q-46 - 7q-44 - 7q-43 + 6q-41 + 8q-40 + 2q-39 - 7q-38 - 9q-37 - 2q-36 + 6q-35 + 10q-34 + 3q-33 - 6q-32 - 10q-31 - 4q-30 + 5q-29 + 11q-28 + 4q-27 - 5q-26 - 10q-25 - 6q-24 + 4q-23 + 12q-22 + 5q-21 - 4q-20 - 11q-19 - 7q-18 + 5q-17 + 13q-16 + 7q-15 - 5q-14 - 13q-13 - 7q-12 + 5q-11 + 12q-10 + 9q-9 - 5q-8 - 13q-7 - 7q-6 + 4q-5 + 9q-4 + 9q-3 - 3q-2 - 11q-1 - 5 + 3q + 7q2 + 6q3 - 3q4 - 8q5 - 2q6 + 3q7 + 4q8 + 4q9 - 3q10 - 6q11 + q12 + 2q13 + 2q14 + 2q15 - q16 - 4q17 + q18 + q19 + q21 - 2q23 + q24 - q29 + q30 |
6 | q-126 - q-125 - q-124 + q-121 + 3q-119 - q-118 - 2q-117 - q-116 - q-115 - q-113 + 6q-112 - q-110 - q-109 - 2q-108 - q-107 - 4q-106 + 7q-105 + q-104 - q-101 - q-100 - 6q-99 + 7q-98 - 7q-92 + 7q-91 + q-89 - q-87 - q-86 - 8q-85 + 7q-84 + 4q-82 + 2q-81 - q-80 - 2q-79 - 11q-78 + 5q-77 - q-76 + 7q-75 + 5q-74 + q-73 - q-72 - 14q-71 + q-70 - 4q-69 + 8q-68 + 7q-67 + 4q-66 + 2q-65 - 15q-64 - q-63 - 7q-62 + 7q-61 + 7q-60 + 6q-59 + 6q-58 - 15q-57 - q-56 - 9q-55 + 5q-54 + 5q-53 + 5q-52 + 9q-51 - 13q-50 - 9q-48 + 4q-47 + 2q-46 + 3q-45 + 11q-44 - 10q-43 + 2q-42 - 9q-41 + 3q-40 - q-39 + 14q-37 - 7q-36 + 3q-35 - 9q-34 + 2q-33 - 4q-32 - 2q-31 + 16q-30 - 5q-29 + 3q-28 - 10q-27 + q-26 - 5q-25 - 2q-24 + 18q-23 - 4q-22 + 2q-21 - 11q-20 - 5q-18 - q-17 + 20q-16 - 3q-15 + 3q-14 - 12q-13 - q-12 - 6q-11 - 2q-10 + 18q-9 - 3q-8 + 6q-7 - 9q-6 - 6q-4 - 3q-3 + 13q-2 - 5q-1 + 6 - 6q + 3q2 - 3q3 - 2q4 + 8q5 - 8q6 + 3q7 - 5q8 + 5q9 + q10 + 5q12 - 9q13 + q14 - 4q15 + 5q16 + 2q17 + q18 + 3q19 - 7q20 + q21 - 3q22 + 3q23 + q24 + q25 + 2q26 - 4q27 + 2q28 - 2q29 + q30 + q33 - 2q34 + 2q35 - q36 - q41 + q42 |
Computer Talk. The data above can be recomputed by Mathematica using the package KnotTheory`. Following setup, the sample Mathematica session below reproduces most of the above data (Mathematica system prompts in blue, human input in red, Mathematica output in black):
In[1]:= |
<< KnotTheory` |
Loading KnotTheory` (version of August 30, 2005, 10:15:35)... | |
In[2]:= | PD[Knot[8, 1]] |
Out[2]= | PD[X[1, 4, 2, 5], X[9, 12, 10, 13], X[3, 11, 4, 10], X[11, 3, 12, 2], > X[5, 16, 6, 1], X[7, 14, 8, 15], X[13, 8, 14, 9], X[15, 6, 16, 7]] |
In[3]:= | GaussCode[Knot[8, 1]] |
Out[3]= | GaussCode[-1, 4, -3, 1, -5, 8, -6, 7, -2, 3, -4, 2, -7, 6, -8, 5] |
In[4]:= | DTCode[Knot[8, 1]] |
Out[4]= | DTCode[4, 10, 16, 14, 12, 2, 8, 6] |
In[5]:= | br = BR[Knot[8, 1]] |
Out[5]= | BR[5, {-1, -1, -2, 1, -2, -3, 2, 4, -3, 4}] |
In[6]:= | {First[br], Crossings[br]} |
Out[6]= | {5, 10} |
In[7]:= | BraidIndex[Knot[8, 1]] |
Out[7]= | 5 |
In[8]:= | Show[DrawMorseLink[Knot[8, 1]]] |
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Out[8]= | -Graphics- |
In[9]:= | #[Knot[8, 1]]& /@ {SymmetryType, UnknottingNumber, ThreeGenus, BridgeIndex, SuperBridgeIndex, NakanishiIndex} |
Out[9]= | {Reversible, 1, 1, 2, {4, 5}, 1} |
In[10]:= | alex = Alexander[Knot[8, 1]][t] |
Out[10]= | 3 7 - - - 3 t t |
In[11]:= | Conway[Knot[8, 1]][z] |
Out[11]= | 2 1 - 3 z |
In[12]:= | Select[AllKnots[], (alex === Alexander[#][t])&] |
Out[12]= | {Knot[8, 1]} |
In[13]:= | {KnotDet[Knot[8, 1]], KnotSignature[Knot[8, 1]]} |
Out[13]= | {13, 0} |
In[14]:= | Jones[Knot[8, 1]][q] |
Out[14]= | -6 -5 -4 2 2 2 2 2 + q - q + q - -- + -- - - - q + q 3 2 q q q |
In[15]:= | Select[AllKnots[], (J === Jones[#][q] || (J /. q-> 1/q) === Jones[#][q])&] |
Out[15]= | {Knot[8, 1], Knot[11, NonAlternating, 70]} |
In[16]:= | A2Invariant[Knot[8, 1]][q] |
Out[16]= | -20 -18 -12 -10 2 6 8 q + q - q - q + q + q + q |
In[17]:= | HOMFLYPT[Knot[8, 1]][a, z] |
Out[17]= | -2 4 6 2 2 2 4 2 a - a + a - z - a z - a z |
In[18]:= | Kauffman[Knot[8, 1]][a, z] |
Out[18]= | 2 3 -2 4 6 3 5 z 4 2 6 2 z 3 -a - a - a - 3 a z - 3 a z + -- + 7 a z + 6 a z + -- - a z + 2 a a 3 3 5 3 4 2 4 4 4 6 4 5 3 5 > 5 a z + 7 a z + z - 2 a z - 8 a z - 5 a z + a z - 4 a z - 5 5 2 6 4 6 6 6 3 7 5 7 > 5 a z + a z + 2 a z + a z + a z + a z |
In[19]:= | {Vassiliev[2][Knot[8, 1]], Vassiliev[3][Knot[8, 1]]} |
Out[19]= | {-3, 3} |
In[20]:= | Kh[Knot[8, 1]][q, t] |
Out[20]= | 1 1 1 1 1 1 1 1 1 1 - + 2 q + ------ + ----- + ----- + ----- + ----- + ----- + ----- + ---- + --- + q 13 6 9 5 9 4 7 3 5 3 5 2 3 2 3 q t q t q t q t q t q t q t q t q t 5 2 > q t + q t |
In[21]:= | ColouredJones[Knot[8, 1], 2][q] |
Out[21]= | -18 -17 -16 2 -14 2 3 3 3 3 3 -5 2 + q - q - q + --- - q - --- + --- - --- + -- - -- + -- + q - 15 13 12 10 9 7 6 q q q q q q q 3 2 -2 3 2 3 5 6 > -- + -- + q - - - 2 q + 2 q - q + q 4 3 q q q |
Dror Bar-Natan: The Knot Atlas: The Rolfsen Knot Table: The Knot 81 |
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