7 2

From Knot Atlas
Jump to navigationJump to search

7 1.gif

7_1

7 3.gif

7_3

7 2.gif
(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 at Knotilus!


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
BraidPart3.gifBraidPart3.gifBraidPart3.gifBraidPart0.gifBraidPart1.gifBraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart0.gif
BraidPart4.gifBraidPart4.gifBraidPart4.gifBraidPart3.gifBraidPart2.gifBraidPart3.gifBraidPart0.gifBraidPart1.gifBraidPart0.gif
BraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart4.gifBraidPart0.gifBraidPart4.gifBraidPart3.gifBraidPart2.gifBraidPart3.gif
BraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart4.gifBraidPart0.gifBraidPart4.gif

Length is 9, width is 4,

Braid index is 4

7 2 ML.gif 7 2 AP.gif
[{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]

Knot 7_2.
A graph, knot 7_2.

Three dimensional invariants

Symmetry type Reversible
Unknotting number 1
3-genus 1
Bridge index 2
Super bridge index [math]\displaystyle{ \{3,4\} }[/math]
Nakanishi index 1
Maximal Thurston-Bennequin number [math]\displaystyle{ \text{$\$$Failed} }[/math]
Hyperbolic Volume 3.33174
A-Polynomial See Data:7 2/A-polynomial

[edit Notes for 7 2's three dimensional invariants]

Four dimensional invariants

Smooth 4 genus [math]\displaystyle{ 1 }[/math]
Topological 4 genus [math]\displaystyle{ 1 }[/math]
Concordance genus [math]\displaystyle{ \textrm{ConcordanceGenus}(\textrm{Knot}(7,2)) }[/math]
Rasmussen s-Invariant -2

[edit Notes for 7 2's four dimensional invariants]

Polynomial invariants

Alexander polynomial [math]\displaystyle{ 3 t+3 t^{-1} -5 }[/math]
Conway polynomial [math]\displaystyle{ 3 z^2+1 }[/math]
2nd Alexander ideal (db, data sources) [math]\displaystyle{ \{1\} }[/math]
Determinant and Signature { 11, -2 }
Jones polynomial [math]\displaystyle{ - q^{-8} + q^{-7} - q^{-6} +2 q^{-5} -2 q^{-4} +2 q^{-3} - q^{-2} + q^{-1} }[/math]
HOMFLY-PT polynomial (db, data sources) [math]\displaystyle{ -a^8+a^6 z^2+a^6+a^4 z^2+a^2 z^2+a^2 }[/math]
Kauffman polynomial (db, data sources) [math]\displaystyle{ a^9 z^5-4 a^9 z^3+3 a^9 z+a^8 z^6-4 a^8 z^4+4 a^8 z^2-a^8+2 a^7 z^5-6 a^7 z^3+3 a^7 z+a^6 z^6-3 a^6 z^4+3 a^6 z^2-a^6+a^5 z^5-a^5 z^3+a^4 z^4+a^3 z^3+a^2 z^2-a^2 }[/math]
The A2 invariant [math]\displaystyle{ -q^{26}-q^{24}+q^{18}+q^{16}+q^8+q^6+q^2 }[/math]
The G2 invariant [math]\displaystyle{ q^{128}+q^{124}-q^{122}-q^{116}+2 q^{114}-2 q^{112}-q^{110}-q^{106}-2 q^{102}-2 q^{100}-q^{92}-q^{90}+2 q^{88}+q^{78}+3 q^{74}+q^{70}+q^{68}-q^{66}+2 q^{64}-q^{60}+q^{54}-q^{50}-q^{40}+q^{38}+q^{36}+q^{34}+q^{28}+q^{24}+q^{20}+q^{14}+q^{10} }[/math]

"Similar" Knots (within the Atlas)

Same Alexander/Conway Polynomial: {}

Same Jones Polynomial (up to mirroring, [math]\displaystyle{ q\leftrightarrow q^{-1} }[/math]): {K11n88,}

Vassiliev invariants

V2 and V3: (3, -6)
V2,1 through V6,9:
V2,1 V3,1 V4,1 V4,2 V4,3 V5,1 V5,2 V5,3 V5,4 V6,1 V6,2 V6,3 V6,4 V6,5 V6,6 V6,7 V6,8 V6,9
[math]\displaystyle{ 12 }[/math] [math]\displaystyle{ -48 }[/math] [math]\displaystyle{ 72 }[/math] [math]\displaystyle{ 222 }[/math] [math]\displaystyle{ 34 }[/math] [math]\displaystyle{ -576 }[/math] [math]\displaystyle{ -1152 }[/math] [math]\displaystyle{ -192 }[/math] [math]\displaystyle{ -176 }[/math] [math]\displaystyle{ 288 }[/math] [math]\displaystyle{ 1152 }[/math] [math]\displaystyle{ 2664 }[/math] [math]\displaystyle{ 408 }[/math] [math]\displaystyle{ \frac{60431}{10} }[/math] [math]\displaystyle{ -\frac{826}{15} }[/math] [math]\displaystyle{ \frac{38942}{15} }[/math] [math]\displaystyle{ \frac{497}{6} }[/math] [math]\displaystyle{ \frac{3471}{10} }[/math]

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 [math]\displaystyle{ t^rq^j }[/math] are shown, along with their alternating sums [math]\displaystyle{ \chi }[/math] (fixed [math]\displaystyle{ j }[/math], alternation over [math]\displaystyle{ r }[/math]). The squares with yellow highlighting are those on the "critical diagonals", where [math]\displaystyle{ j-2r=s+1 }[/math] or [math]\displaystyle{ j-2r=s-1 }[/math], where [math]\displaystyle{ s= }[/math]-2 is the signature of 7 2. Nonzero entries off the critical diagonals (if any exist) are highlighted in red.   
\ r
  \  
j \
-7-6-5-4-3-2-10χ
-1       11
-3      110
-5     1  1
-7    11  0
-9   11   0
-11   1    1
-13 11     0
-15        0
-171       -1
Integral Khovanov Homology

(db, data source)

  
[math]\displaystyle{ \dim{\mathcal G}_{2r+i}\operatorname{KH}^r_{\mathbb Z} }[/math] [math]\displaystyle{ i=-3 }[/math] [math]\displaystyle{ i=-1 }[/math]
[math]\displaystyle{ r=-7 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]
[math]\displaystyle{ r=-6 }[/math] [math]\displaystyle{ {\mathbb Z}_2 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]
[math]\displaystyle{ r=-5 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]
[math]\displaystyle{ r=-4 }[/math] [math]\displaystyle{ {\mathbb Z}\oplus{\mathbb Z}_2 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]
[math]\displaystyle{ r=-3 }[/math] [math]\displaystyle{ {\mathbb Z}\oplus{\mathbb Z}_2 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]
[math]\displaystyle{ r=-2 }[/math] [math]\displaystyle{ {\mathbb Z}\oplus{\mathbb Z}_2 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]
[math]\displaystyle{ r=-1 }[/math] [math]\displaystyle{ {\mathbb Z}_2 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]
[math]\displaystyle{ r=0 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]

The Coloured Jones Polynomials