7 4

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7 3.gif

7_3

7 5.gif

7_5

7 4.gif
(KnotPlot image)

See the full Rolfsen Knot Table.

Visit 7 4's page at the Knot Server (KnotPlot driven, includes 3D interactive images!)

Visit 7 4 at Knotilus!

Simplest version of Endless knot symbol.

Celtic or pseudo-Celtic knot
Mongolian ornament
Susan Williams' medallion [1], the "Endless knot" of Buddhism [2]
Ornamental "Endless knot"
a knot seen at the Castle of Kornik [3]
A 7-4 knot reduced from TakaraMusubi with 9 crossings [4]
TakaraMusubi knot seen in Japanese symbols, or Kolam in South India [5]
Buddhist Endless Knot
Ornamental Endless Knot
Albrecht Dürer knot, 16th-century
A laser cut by Tom Longtin [6]
Unicursal hexagram of occultism
Logo of the raelian sect
Lissajous curve : x=cos 3t , y=sin 2t, z=sin 7t
French europa stamp 2023


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]


Minimum Braid Representative A Morse Link Presentation An Arc Presentation
BraidPart1.gifBraidPart1.gifBraidPart0.gifBraidPart3.gifBraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart0.gif
BraidPart2.gifBraidPart2.gifBraidPart1.gifBraidPart4.gifBraidPart1.gifBraidPart1.gifBraidPart0.gifBraidPart3.gifBraidPart0.gif
BraidPart0.gifBraidPart0.gifBraidPart2.gifBraidPart0.gifBraidPart2.gifBraidPart2.gifBraidPart1.gifBraidPart4.gifBraidPart1.gif
BraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart0.gifBraidPart2.gifBraidPart0.gifBraidPart2.gif

Length is 9, width is 4,

Braid index is 4

7 4 ML.gif 7 4 AP.gif
[{3, 5}, {6, 4}, {5, 7}, {2, 6}, {8, 3}, {7, 9}, {1, 8}, {9, 2}, {4, 1}]

[edit Notes on presentations of 7 4]

Knot 7_4.
A graph, knot 7_4.

Three dimensional invariants

Symmetry type Reversible
Unknotting number 2
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 5.13794
A-Polynomial See Data:7 4/A-polynomial

[edit Notes for 7 4'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}(7,4)) }[/math]
Rasmussen s-Invariant -2

[edit Notes for 7 4's four dimensional invariants]

Polynomial invariants

Alexander polynomial [math]\displaystyle{ 4 t+4 t^{-1} -7 }[/math]
Conway polynomial [math]\displaystyle{ 4 z^2+1 }[/math]
2nd Alexander ideal (db, data sources) [math]\displaystyle{ \{1\} }[/math]
Determinant and Signature { 15, 2 }
Jones polynomial [math]\displaystyle{ -q^8+q^7-2 q^6+3 q^5-2 q^4+3 q^3-2 q^2+q }[/math]
HOMFLY-PT polynomial (db, data sources) [math]\displaystyle{ - a^{-8} +z^2 a^{-6} +2 z^2 a^{-4} +2 a^{-4} +z^2 a^{-2} }[/math]
Kauffman polynomial (db, data sources) [math]\displaystyle{ z^6 a^{-6} +z^6 a^{-8} +2 z^5 a^{-5} +3 z^5 a^{-7} +z^5 a^{-9} +3 z^4 a^{-4} -3 z^4 a^{-8} +2 z^3 a^{-3} -2 z^3 a^{-5} -8 z^3 a^{-7} -4 z^3 a^{-9} +z^2 a^{-2} -4 z^2 a^{-4} -3 z^2 a^{-6} +2 z^2 a^{-8} +4 z a^{-7} +4 z a^{-9} +2 a^{-4} - a^{-8} }[/math]
The A2 invariant [math]\displaystyle{ q^{-2} - q^{-4} + q^{-8} + q^{-10} +2 q^{-12} + q^{-14} + q^{-16} - q^{-20} - q^{-24} - q^{-26} }[/math]
The G2 invariant [math]\displaystyle{ q^{-10} - q^{-12} + q^{-14} - q^{-16} - q^{-22} +4 q^{-24} -2 q^{-26} +2 q^{-28} - q^{-30} + q^{-34} -2 q^{-36} +3 q^{-38} -2 q^{-40} + q^{-44} +2 q^{-48} + q^{-50} - q^{-52} +2 q^{-54} - q^{-56} +3 q^{-58} + q^{-60} -2 q^{-62} +6 q^{-64} -3 q^{-66} +4 q^{-68} +2 q^{-70} -3 q^{-72} +4 q^{-74} -3 q^{-76} +3 q^{-78} - q^{-80} - q^{-82} + q^{-84} -2 q^{-86} +2 q^{-88} -3 q^{-92} - q^{-94} -2 q^{-96} -4 q^{-102} +2 q^{-104} -3 q^{-106} + q^{-108} + q^{-110} -4 q^{-112} +3 q^{-114} -2 q^{-116} + q^{-118} -2 q^{-122} +2 q^{-124} + q^{-128} }[/math]

"Similar" Knots (within the Atlas)

Same Alexander/Conway Polynomial: {9_2,}

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

Vassiliev invariants

V2 and V3: (4, 8)
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{ 16 }[/math] [math]\displaystyle{ 64 }[/math] [math]\displaystyle{ 128 }[/math] [math]\displaystyle{ \frac{1016}{3} }[/math] [math]\displaystyle{ \frac{184}{3} }[/math] [math]\displaystyle{ 1024 }[/math] [math]\displaystyle{ \frac{5824}{3} }[/math] [math]\displaystyle{ \frac{1024}{3} }[/math] [math]\displaystyle{ 320 }[/math] [math]\displaystyle{ \frac{2048}{3} }[/math] [math]\displaystyle{ 2048 }[/math] [math]\displaystyle{ \frac{16256}{3} }[/math] [math]\displaystyle{ \frac{2944}{3} }[/math] [math]\displaystyle{ \frac{168062}{15} }[/math] [math]\displaystyle{ -\frac{1176}{5} }[/math] [math]\displaystyle{ \frac{233288}{45} }[/math] [math]\displaystyle{ \frac{898}{9} }[/math] [math]\displaystyle{ \frac{11102}{15} }[/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 4. Nonzero entries off the critical diagonals (if any exist) are highlighted in red.   
\ r
  \  
j \
01234567χ
17       1-1
15        0
13     21 -1
11    1   1
9   12   1
7  21    1
5  1     1
312      -1
11       1
Integral Khovanov Homology

(db, data source)

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

The Coloured Jones Polynomials