7 2
From Knot Atlas
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![]() (KnotPlot image) |
See the full Rolfsen Knot Table. Visit 7 2's page at the Knot Server (KnotPlot driven, includes 3D interactive images!) Visit 7_2's page at Knotilus! Visit 7 2's page at the original Knot Atlas! |
[edit] Knot presentations
| Planar diagram presentation | X1425 X3,10,4,11 X5,14,6,1 X7,12,8,13 X11,8,12,9 X13,6,14,7 X9,2,10,3 |
| Gauss code | -1, 7, -2, 1, -3, 6, -4, 5, -7, 2, -5, 4, -6, 3 |
| Dowker-Thistlethwaite code | 4 10 14 12 2 8 6 |
| Conway Notation | [52] |
| Minimum Braid Representative | A Morse Link Presentation | An Arc Presentation | ||||
Length is 9, width is 4, Braid index is 4 |
| ![]() [{9, 6}, {5, 7}, {6, 4}, {3, 5}, {4, 2}, {1, 3}, {2, 8}, {7, 9}, {8, 1}] |
[edit Notes on presentations of 7 2]
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]:=
| AppendTo[$Path, "C:/drorbn/projects/KAtlas/"];
<< KnotTheory`
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Loading KnotTheory` version of May 31, 2006, 14:15:20.091.
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In[3]:=
| K = Knot["7 2"];
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In[4]:=
| PD[K]
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KnotTheory::loading: Loading precomputed data in PD4Knots`.
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Out[4]=
| X1425 X3,10,4,11 X5,14,6,1 X7,12,8,13 X11,8,12,9 X13,6,14,7 X9,2,10,3 |
In[5]:=
| GaussCode[K]
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Out[5]=
| -1, 7, -2, 1, -3, 6, -4, 5, -7, 2, -5, 4, -6, 3 |
In[6]:=
| DTCode[K]
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Out[6]=
| 4 10 14 12 2 8 6 |
(The path below may be different on your system)
In[7]:=
| AppendTo[$Path, "C:/bin/LinKnot/"];
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In[8]:=
| ConwayNotation[K]
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Out[8]=
| [52] |
In[9]:=
| 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]=
| BR(4,{−1,−1,−1,−2,1,−2,−3,2,−3}) |
In[10]:=
| {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]=
| { 4, 9, 4 } |
In[11]:=
| Show[BraidPlot[br]]
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Out[11]=
| -Graphics- |
In[12]:=
| 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]=
| -Graphics- |
In[13]:=
| ap = ArcPresentation[K]
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Out[13]=
| ArcPresentation[{9, 6}, {5, 7}, {6, 4}, {3, 5}, {4, 2}, {1, 3}, {2, 8}, {7, 9}, {8, 1}] |
In[14]:=
| Draw[ap]
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Out[14]=
| -Graphics- |
[edit] Three dimensional invariants
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[edit] Four dimensional invariants
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[edit] Polynomial invariants
| Alexander polynomial | 3t−5 + 3t−1 |
| Conway polynomial | 3z2 + 1 |
| 2nd Alexander ideal (db, data sources) | {1} |
| Determinant and Signature | { 11, -2 } |
| Jones polynomial | q−1−q−2 + 2q−3−2q−4 + 2q−5−q−6 + q−7−q−8 |
| HOMFLY-PT polynomial (db, data sources) | −a8 + z2a6 + a6 + z2a4 + z2a2 + a2 |
| Kauffman polynomial (db, data sources) | z5a9−4z3a9 + 3za9 + z6a8−4z4a8 + 4z2a8−a8 + 2z5a7−6z3a7 + 3za7 + z6a6−3z4a6 + 3z2a6−a6 + z5a5−z3a5 + z4a4 + z3a3 + z2a2−a2 |
| The A2 invariant | −q26−q24 + q18 + q16 + q8 + q6 + q2 |
| The G2 invariant | q128 + q124−q122−q116 + 2q114−2q112−q110−q106−2q102−2q100−q92−q90 + 2q88 + q78 + 3q74 + q70 + q68−q66 + 2q64−q60 + q54−q50−q40 + q38 + q36 + q34 + q28 + q24 + q20 + q14 + q10 |
A1 Invariants.
| Weight | Invariant |
|---|---|
| 1 | −q17 + q11 + q5 + q |
| 2 | q48−q44−q38 + q34−q26−q24 + 2q14 + q12 + q8 + q2 |
| 3 | −q93 + q89 + q87−q83 + q79−q75−q73 + q69 + q61 + q59−q55−q49−q47−q41−q39 + q33−q29 + q25 + q23 + q17 + q15 + q13 + q11 + q3 |
| 4 | q152−q148−q146−q144 + q142 + q140 + q138−2q134 + q130 + q128 + q126−q124−q122−q120 + q116−q110−q108 + q104 + 2q102−q98 + q94 + 2q92−2q88−q86 + q82−q78 + q74 + q72−q68 + q64−q60−q58−2q56−2q54−q52 + q50 + q48−q46−q44−2q42 + q40 + 3q38 + 2q36−2q32 + 2q28 + q26 + q24−q22 + q18 + q16 + 2q14 + q4 |
| 5 | −q225 + q221 + q219 + q217−q213−2q211−q209 + q205 + 2q203 + q201−q199−2q197−q195 + q191 + 2q189 + q187−q183−q181−q179 + q175 + q173 + q171−q167−2q165−2q163 + 2q159 + 2q157−2q153−2q151−q149 + 2q147 + 4q145 + 2q143−q141−2q139−2q137 + 2q133 + q131−q129−3q127−2q125 + 2q121 + 2q119 + q117−q115−q113 + q111 + 2q109 + q107−q103 + 2q99 + q97−q93−q91−q89−3q77−3q75−2q73 + q71 + 2q69 + 3q67 + q65−3q63−5q61−3q59 + 2q57 + 4q55 + 3q53−q51−4q49−3q47 + q45 + 4q43 + 3q41−q37−q35 + q33 + 2q31 + 2q29−q25 + q19 + 2q17 + q15 + q5 |
| 6 | q312−q308−q306−q304 + 2q298 + 2q296 + q294−q290−2q288−3q286 + q282 + 2q280 + 2q278 + q276−3q272−2q270−q268 + q264 + 2q262 + 2q260−q254−q252−2q250−q248 + q246 + q244 + 2q242 + 2q240 + 2q238−q236−3q234−3q232−2q230 + q228 + 3q226 + 4q224 + q222−2q220−4q218−5q216−2q214 + 2q212 + 5q210 + 4q208 + 2q206−q204−4q202−3q200 + 3q196 + 4q194 + 3q192−4q188−5q186−3q184 + 2q180 + 3q178 + 2q176−2q174−4q172−2q170 + q168 + 3q166 + 3q164 + 2q162−q160−4q158−2q156 + q154 + 2q152 + 2q150 + q148−q146−2q144 + 2q140 + q138−q134−q132−q130 + q128 + 2q126 + 2q124 + q122−q114−q112 + q110 + 2q108 + 2q106 + q104−q102−4q100−6q98−4q96−q94 + 2q92 + 6q90 + 4q88−q86−6q84−7q82−5q80 + 6q76 + 7q74 + 3q72−3q70−5q68−4q66−q64 + 4q62 + 4q60 + q58−2q56−2q54−q52 + 3q48 + 2q46−q42 + q38 + q36 + 3q34 + q32−q28 + 2q20 + q18 + q16 + q6 |
A2 Invariants.
| Weight | Invariant |
|---|---|
| 1,0 | −q26−q24 + q18 + q16 + q8 + q6 + q2 |
| 1,1 | q68 + 2q64−2q62 + 2q60−4q58−2q54 + 2q50 + 4q46−3q44 + 2q42−4q40 + 2q38−4q36−2q32−2q30 + 2q24 + 2q22 + 3q20 + 2q18 + 2q16 + 2q12 + 2q8 + q4 |
| 2,0 | q66 + q64 + q62−q60−q58−q56−q54−q52−q50 + q48 + q46 + q44−q38−2q36−2q34−q32 + q26 + q24 + q22 + 3q20 + 2q18 + q16 + q12 + q10 + q4 |
| 3,0 | −q120−q118−q116 + 2q112 + 2q110 + 2q108−2q96−2q94−2q92 + q88 + q86 + q84 + q82 + 2q80 + 3q78 + 2q76−q72−2q70−q68−3q66−3q64−3q62−q60−q56−q54−q52−q48−q40−q38 + 2q36 + 3q34 + 3q32 + 2q30 + 2q26 + 3q24 + 3q22 + q20 + q16 + q14 + q6 |
A3 Invariants.
| Weight | Invariant |
|---|---|
| 0,1,0 | q54 + q50−q46−q44−2q42−2q40−q38−q34 + q32 + q30 + q28 + q26 + q24 + q22 + q16 + q12 + 2q10 + q8 + q4 |
| 1,0,0 | −q35−q33−q31 + q25 + q23 + q21 + q11 + q9 + q7 + q3 |
A4 Invariants.
| Weight | Invariant |
|---|---|
| 0,1,0,0 | q72 + q70 + q68 + q66 + q64−q62−2q60−2q58−2q56−3q54−3q52−q50−q48−q46 + q42 + q40 + 2q38 + 2q36 + 2q34 + q32 + q30 + q28 + q22 + q20 + q18 + q16 + 2q14 + 2q12 + q10 + q6 |
| 1,0,0,0 | −q44−q42−q40−q38 + q32 + q30 + q28 + q26 + q14 + q12 + q10 + q8 + q4 |
B2 Invariants.
| Weight | Invariant |
|---|---|
| 0,1 | −q54−q50−q46 + q44 + q38 + q34−q32 + q30−q28 + q26−q24 + q22 + q16 + q12 + q8 + q4 |
| 1,0 | q88 + q80−q76−q74−q68−q66−q64−q56 + q44 + q42 + q36 + q34 + q26 + q18 + q16 + q14 + q6 |
D4 Invariants.
| Weight | Invariant |
|---|---|
| 1,0,0,0 | q74 + q70 + q66−q64−q62−2q60−2q58−2q56−2q54−q52−q50 + q48 + 2q44 + q42 + 2q40 + 2q36 + q32 + q22 + q18 + q16 + 2q14 + q12 + q10 + q6 |
G2 Invariants.
| Weight | Invariant |
|---|---|
| 1,0 | q128 + q124−q122−q116 + 2q114−2q112−q110−q106−2q102−2q100−q92−q90 + 2q88 + q78 + 3q74 + q70 + q68−q66 + 2q64−q60 + q54−q50−q40 + q38 + q36 + q34 + q28 + q24 + q20 + q14 + q10 |
.
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]:=
| 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]:=
| K = Knot["7 2"];
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In[4]:=
| Alexander[K][t]
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KnotTheory::loading: Loading precomputed data in PD4Knots`.
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Out[4]=
| 3t−5 + 3t−1 |
In[5]:=
| Conway[K][z]
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Out[5]=
| 3z2 + 1 |
In[6]:=
| 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]=
| {1} |
In[7]:=
| {KnotDet[K], KnotSignature[K]}
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Out[7]=
| { 11, -2 } |
In[8]:=
| Jones[K][q]
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KnotTheory::loading: Loading precomputed data in Jones4Knots`.
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Out[8]=
| q−1−q−2 + 2q−3−2q−4 + 2q−5−q−6 + q−7−q−8 |
In[9]:=
| HOMFLYPT[K][a, z]
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KnotTheory::credits: The HOMFLYPT program was written by Scott Morrison.
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Out[9]=
| −a8 + z2a6 + a6 + z2a4 + z2a2 + a2 |
In[10]:=
| Kauffman[K][a, z]
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KnotTheory::loading: Loading precomputed data in Kauffman4Knots`.
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Out[10]=
| z5a9−4z3a9 + 3za9 + z6a8−4z4a8 + 4z2a8−a8 + 2z5a7−6z3a7 + 3za7 + z6a6−3z4a6 + 3z2a6−a6 + z5a5−z3a5 + z4a4 + z3a3 + z2a2−a2 |
[edit] "Similar" Knots (within the Atlas)
Same Alexander/Conway Polynomial: {}
Same Jones Polynomial (up to mirroring,
):
{K11n88,}
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]:=
| AppendTo[$Path, "C:/drorbn/projects/KAtlas/"];
<< KnotTheory`
|
Loading KnotTheory` version of May 31, 2006, 14:15:20.091.
|
In[3]:=
| K = Knot["7 2"];
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In[4]:=
| {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]=
| { 3t−5 + 3t−1, q−1−q−2 + 2q−3−2q−4 + 2q−5−q−6 + q−7−q−8 } |
In[5]:=
| 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]=
| {} |
In[6]:=
| 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]=
| {K11n88,} |
[edit] Khovanov Homology
| The coefficients of the monomials trqj are shown, along with their alternating sums χ (fixed j, alternation over r). The squares with yellow highlighting are those on the "critical diagonals", where j−2r = s + 1 or j−2r = s−1, where s = -2 is the signature of 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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[edit] The Coloured Jones Polynomials
| n | Jn |
| 2 | q−2−q−3 + 2q−5−2q−6 + q−7 + 3q−8−4q−9 + q−10 + 3q−11−4q−12 + 3q−14−3q−15 + 3q−17−2q−18−q−19 + 2q−20−q−21−q−22 + q−23 |
| 3 | q−3−q−4 + 2q−7−q−8 + q−11−q−12 + q−13−2q−16 + 2q−17 + q−18−q−19−2q−20 + q−21 + q−22−2q−24 + q−26 + q−27−2q−28−q−29 + 2q−30 + 2q−31−2q−32−2q−33 + 2q−34 + 2q−35−q−36−3q−37 + q−38 + 2q−39−2q−41 + q−43 + q−44−q−45 |
| 4 | q−4−q−5 + 3q−9−2q−10−q−12−q−13 + 5q−14−2q−15 + q−16−3q−17−3q−18 + 7q−19 + 2q−21−5q−22−6q−23 + 8q−24 + 4q−26−5q−27−8q−28 + 7q−29 + 5q−31−5q−32−7q−33 + 8q−34−q−35 + 4q−36−4q−37−6q−38 + 8q−39−2q−40 + 3q−41−3q−42−5q−43 + 7q−44−3q−45 + 2q−46−q−47−3q−48 + 6q−49−4q−50 + q−51−q−53 + 5q−54−5q−55 + 5q−59−4q−60−q−61−q−62 + 5q−64−2q−65−q−66−q−67−q−68 + 3q−69−q−72−q−73 + q−74 |
| 5 | q−5−q−6 + q−10 + 2q−11−2q−12−q−13−q−15 + 2q−16 + 4q−17−2q−18−2q−19−2q−20−q−21 + 3q−22 + 7q−23−q−24−5q−25−6q−26−2q−27 + 6q−28 + 11q−29−7q−31−11q−32−4q−33 + 8q−34 + 15q−35 + 2q−36−8q−37−12q−38−7q−39 + 7q−40 + 15q−41 + 5q−42−8q−43−12q−44−7q−45 + 7q−46 + 14q−47 + 5q−48−8q−49−11q−50−6q−51 + 8q−52 + 12q−53 + 4q−54−7q−55−10q−56−5q−57 + 7q−58 + 10q−59 + 4q−60−5q−61−9q−62−5q−63 + 5q−64 + 8q−65 + 3q−66−3q−67−7q−68−4q−69 + 3q−70 + 6q−71 + 3q−72−2q−73−4q−74−2q−75 + q−76 + 3q−77 + 2q−78−2q−79−2q−80 + q−82 + q−83−2q−85−q−86 + q−87 + 2q−88 + q−89−3q−91−2q−92 + q−93 + 2q−94 + 2q−95 + q−96−2q−97−3q−98 + q−100 + q−101 + 2q−102−2q−104−q−105 + q−108 + q−109−q−110 |
| 6 | q−6−q−7 + q−11 + 2q−13−3q−14−q−17 + 2q−18 + q−19 + 4q−20−5q−21−q−23−2q−24 + 3q−25 + 3q−26 + 5q−27−8q−28−q−29−2q−30−2q−31 + 6q−32 + 6q−33 + 5q−34−13q−35−4q−36−3q−37 + 12q−39 + 10q−40 + 4q−41−19q−42−9q−43−5q−44 + q−45 + 17q−46 + 15q−47 + 6q−48−23q−49−12q−50−8q−51−q−52 + 19q−53 + 18q−54 + 8q−55−22q−56−12q−57−9q−58−3q−59 + 19q−60 + 19q−61 + 8q−62−22q−63−11q−64−8q−65−3q−66 + 18q−67 + 17q−68 + 8q−69−22q−70−10q−71−7q−72−2q−73 + 16q−74 + 15q−75 + 9q−76−20q−77−9q−78−7q−79−3q−80 + 13q−81 + 13q−82 + 12q−83−17q−84−8q−85−7q−86−5q−87 + 10q−88 + 11q−89 + 14q−90−13q−91−7q−92−8q−93−7q−94 + 7q−95 + 9q−96 + 15q−97−9q−98−4q−99−7q−100−8q−101 + 4q−102 + 6q−103 + 14q−104−6q−105−q−106−5q−107−7q−108 + q−109 + 2q−110 + 11q−111−5q−112 + q−113−2q−114−4q−115 + 8q−118−6q−119 + q−120−q−122 + 7q−125−6q−126−q−127−q−128 + q−131 + 7q−132−4q−133−q−134−2q−135−q−136−q−137 + 6q−139−q−140−q−142−q−143−2q−144−q−145 + 3q−146 + q−148−q−151−q−152 + q−153 |
| 7 | q−7−q−8 + q−12 + q−15−2q−16−q−19 + 2q−20 + q−21 + q−22 + 2q−23−4q−24−q−26−2q−27 + 2q−28 + 2q−29 + 2q−30 + 3q−31−5q−32−q−33−q−34−2q−35 + 3q−36 + q−37 + q−38 + 4q−39−6q−40−q−41 + q−42 + q−43 + 4q−44−2q−45−3q−46−q−47−7q−48 + 2q−49 + 7q−50 + 6q−51 + 7q−52−4q−53−10q−54−9q−55−11q−56 + 5q−57 + 12q−58 + 13q−59 + 13q−60−4q−61−13q−62−15q−63−17q−64 + 2q−65 + 14q−66 + 17q−67 + 17q−68−2q−69−11q−70−16q−71−20q−72−q−73 + 12q−74 + 18q−75 + 19q−76−q−77−10q−78−15q−79−19q−80−2q−81 + 12q−82 + 17q−83 + 18q−84−2q−85−10q−86−14q−87−18q−88 + 12q−90 + 14q−91 + 17q−92−2q−93−10q−94−13q−95−17q−96 + q−97 + 10q−98 + 10q−99 + 17q−100−8q−102−10q−103−16q−104 + 6q−106 + 6q−107 + 17q−108 + 3q−109−4q−110−7q−111−16q−112−3q−113 + 2q−114 + 3q−115 + 16q−116 + 7q−117 + q−118−3q−119−17q−120−6q−121−3q−122−q−123 + 15q−124 + 9q−125 + 6q−126 + 2q−127−15q−128−9q−129−8q−130−4q−131 + 13q−132 + 9q−133 + 9q−134 + 8q−135−11q−136−9q−137−10q−138−8q−139 + 9q−140 + 6q−141 + 9q−142 + 11q−143−6q−144−6q−145−8q−146−10q−147 + 4q−148 + 2q−149 + 6q−150 + 11q−151−3q−152−2q−153−3q−154−8q−155 + 2q−156−q−157 + 2q−158 + 8q−159−3q−160−5q−163 + 3q−164−q−165 + 5q−167−3q−168−q−169−q−170−4q−171 + 4q−172 + q−173 + 5q−175−2q−176−q−177−2q−178−5q−179 + 2q−180 + q−181 + 4q−183 + q−184 + q−185−q−186−5q−187−q−190 + 2q−191 + q−192 + 2q−193 + q−194−2q−195−q−196−q−198 + q−201 + q−202−q−203 |
[edit] 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.
[edit] 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. |
|



