8 19

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8 18.gif

8_18

8 20.gif

8_20

Contents

8 19.gif
(KnotPlot image)

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Visit 8 19 at Knotilus!

8 19 is the first non-obvious torus knot in the table - it is in fact T(4,3). It is also the pretzel knot P(3,3,-2).

8_19 is the first non-homologically thin knot in the Rolfsen table. (That is, it's the first knot whose Khovanov homology has 'off-diagonal' elements.)

Knotscape
Symmetrical form ; (3,4) torus knot
True-lover's knot with sticked free ends
Equal to the previous, from knotilus
Pretzel knot P(2,-3,-3)
French logo

Knot presentations

Planar diagram presentation X4251 X8493 X9,15,10,14 X5,13,6,12 X13,7,14,6 X11,1,12,16 X15,11,16,10 X2837
Gauss code 1, -8, 2, -1, -4, 5, 8, -2, -3, 7, -6, 4, -5, 3, -7, 6
Dowker-Thistlethwaite code 4 8 -12 2 -14 -16 -6 -10
Conway Notation [3,3,2-]


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

Length is 8, width is 3,

Braid index is 3

8 19 ML.gif 8 19 AP.gif
[{4, 10}, {3, 5}, {1, 4}, {6, 9}, {5, 8}, {2, 6}, {10, 3}, {9, 7}, {8, 2}, {7, 1}]

[edit Notes on presentations of 8 19]

Knot 8_19.
A graph which shows knot 8_19.
A part of a knot and a part of a graph.

Three dimensional invariants

Symmetry type Reversible
Unknotting number 3
3-genus 3
Bridge index 3
Super bridge index 4
Nakanishi index 1
Maximal Thurston-Bennequin number [5][-12]
Hyperbolic Volume Not hyperbolic
A-Polynomial See Data:8 19/A-polynomial

[edit Notes for 8 19's three dimensional invariants]

Four dimensional invariants

Smooth 4 genus 3
Topological 4 genus 3
Concordance genus 3
Rasmussen s-Invariant -6

[edit Notes for 8 19's four dimensional invariants]

Polynomial invariants

Alexander polynomial t^3-t^2+1- t^{-2} + t^{-3}
Conway polynomial z^6+5 z^4+5 z^2+1
2nd Alexander ideal (db, data sources) \{1\}
Determinant and Signature { 3, 6 }
Jones polynomial -q^8+q^5+q^3
HOMFLY-PT polynomial (db, data sources) z^6 a^{-6} +6 z^4 a^{-6} -z^4 a^{-8} +10 z^2 a^{-6} -5 z^2 a^{-8} +5 a^{-6} -5 a^{-8} + a^{-10}
Kauffman polynomial (db, data sources) z^6 a^{-6} +z^6 a^{-8} +z^5 a^{-7} +z^5 a^{-9} -6 z^4 a^{-6} -6 z^4 a^{-8} -5 z^3 a^{-7} -5 z^3 a^{-9} +10 z^2 a^{-6} +10 z^2 a^{-8} +5 z a^{-7} +5 z a^{-9} -5 a^{-6} -5 a^{-8} - a^{-10}
The A2 invariant  q^{-10} + q^{-12} +2 q^{-14} +2 q^{-16} +2 q^{-18} - q^{-22} -2 q^{-24} -2 q^{-26} - q^{-28} + q^{-32}
The G2 invariant  q^{-50} + q^{-52} + q^{-54} + q^{-56} + q^{-58} + q^{-60} +2 q^{-62} +2 q^{-64} + q^{-66} + q^{-68} +2 q^{-70} +2 q^{-72} +2 q^{-74} + q^{-76} + q^{-80} +2 q^{-82} - q^{-94} -2 q^{-96} - q^{-98} - q^{-100} -2 q^{-102} -2 q^{-104} -2 q^{-106} - q^{-108} - q^{-110} -2 q^{-112} -2 q^{-114} - q^{-116} - q^{-122} - q^{-124} + q^{-126} + q^{-128} + q^{-136} + q^{-138} + q^{-144}