8 9

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8 8.gif

8_8

8 10.gif

8_10

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8 9 Quick Notes


8 9 Further Notes and Views

Knot presentations

Planar diagram presentation X6271 X14,8,15,7 X10,3,11,4 X2,13,3,14 X12,5,13,6 X4,11,5,12 X16,10,1,9 X8,16,9,15
Gauss code 1, -4, 3, -6, 5, -1, 2, -8, 7, -3, 6, -5, 4, -2, 8, -7
Dowker-Thistlethwaite code 6 10 12 14 16 4 2 8
Conway Notation [3113]

Three dimensional invariants

Symmetry type Fully amphicheiral
Unknotting number 1
3-genus 3
Bridge index 2
Super bridge index
Nakanishi index 1
Maximal Thurston-Bennequin number [-5][-5]
Hyperbolic Volume 7.58818
A-Polynomial See Data:8 9/A-polynomial

[edit Notes for 8 9's three dimensional invariants]

Four dimensional invariants

Smooth 4 genus
Topological 4 genus
Concordance genus
Rasmussen s-Invariant 0

[edit Notes for 8 9's four dimensional invariants]

Polynomial invariants

Alexander polynomial
Conway polynomial
2nd Alexander ideal (db, data sources)
Determinant and Signature { 25, 0 }
Jones polynomial
HOMFLY-PT polynomial (db, data sources)
Kauffman polynomial (db, data sources)
The A2 invariant
The G2 invariant

Vassiliev invariants

V2 and V3: (-2, 0)
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

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 are shown, along with their alternating sums (fixed , alternation over ). The squares with yellow highlighting are those on the "critical diagonals", where or , where 0 is the signature of 8 9. Nonzero entries off the critical diagonals (if any exist) are highlighted in red.

\ r
  \  
j \
-4-3-2-101234χ
9        11
7       1 -1
5      21 1
3     21  -1
1    32   1
-1   23    1
-3  12     -1
-5 12      1
-7 1       -1
-91        1

Computer Talk

Much of the above data can be recomputed by Mathematica using the package KnotTheory`. See A Sample KnotTheory` Session.

In[1]:=    
<< KnotTheory`
Loading KnotTheory` (version of August 17, 2005, 14:44:34)...
In[2]:=
Crossings[Knot[8, 9]]
Out[2]=  
8
In[3]:=
PD[Knot[8, 9]]
Out[3]=  
PD[X[6, 2, 7, 1], X[14, 8, 15, 7], X[10, 3, 11, 4], X[2, 13, 3, 14], 
  X[12, 5, 13, 6], X[4, 11, 5, 12], X[16, 10, 1, 9], X[8, 16, 9, 15]]
In[4]:=
GaussCode[Knot[8, 9]]
Out[4]=  
GaussCode[1, -4, 3, -6, 5, -1, 2, -8, 7, -3, 6, -5, 4, -2, 8, -7]
In[5]:=
BR[Knot[8, 9]]
Out[5]=  
BR[3, {-1, -1, -1, 2, -1, 2, 2, 2}]
In[6]:=
alex = Alexander[Knot[8, 9]][t]
Out[6]=  
     -3   3    5            2    3

7 - t + -- - - - 5 t + 3 t - t

          2   t
t
In[7]:=
Conway[Knot[8, 9]][z]
Out[7]=  
       2      4    6
1 - 2 z  - 3 z  - z
In[8]:=
Select[AllKnots[], (alex === Alexander[#][t])&]
Out[8]=  
{Knot[8, 9], Knot[10, 155], Knot[11, NonAlternating, 37]}
In[9]:=
{KnotDet[Knot[8, 9]], KnotSignature[Knot[8, 9]]}
Out[9]=  
{25, 0}
In[10]:=
J=Jones[Knot[8, 9]][q]
Out[10]=  
     -4   2    3    4            2      3    4

5 + q - -- + -- - - - 4 q + 3 q - 2 q + q

          3    2   q
q q
In[11]:=
Select[AllKnots[], (J === Jones[#][q] || (J /. q-> 1/q) === Jones[#][q])&]
Out[11]=  
{Knot[8, 9]}
In[12]:=
A2Invariant[Knot[8, 9]][q]
Out[12]=  
      -12    -8    -4    -2    2    4    8    12
-1 + q    + q   - q   + q   + q  - q  + q  + q
In[13]:=
Kauffman[Knot[8, 9]][a, z]
Out[13]=  
                                                  2      2
    2       2   z    z          3         2   2 z    4 z       2  2

-3 - -- - 2 a + -- + - + a z + a z + 12 z - ---- + ---- + 4 a z -

     2           3   a                          4      2
    a           a                              a      a

              3    3                             4      4
    4  2   4 z    z       3      3  3       4   z    4 z       2  4
 2 a  z  - ---- - -- - a z  - 4 a  z  - 10 z  + -- - ---- - 4 a  z  + 
             3    a                              4     2
            a                                   a     a

            5                       6              7
  4  4   2 z       3  5      6   2 z       2  6   z       7
 a  z  + ---- + 2 a  z  + 4 z  + ---- + 2 a  z  + -- + a z
           3                       2              a
a a
In[14]:=
{Vassiliev[2][Knot[8, 9]], Vassiliev[3][Knot[8, 9]]}
Out[14]=  
{0, 0}
In[15]:=
Kh[Knot[8, 9]][q, t]
Out[15]=  
3           1       1       1       2       1      2      2

- + 3 q + ----- + ----- + ----- + ----- + ----- + ---- + --- + 2 q t + q 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

    3      3  2      5  2    5  3    7  3    9  4
2 q t + q t + 2 q t + q t + q t + q t