9 41

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9 40.gif

9_40

9 42.gif

9_42

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9 41 Quick Notes




Three-fold symmetric decorative knot
Three-fold symmetric decorative knot in circle

Knot presentations

Planar diagram presentation X6271 X12,8,13,7 X14,5,15,6 X10,3,11,4 X2,11,3,12 X4,15,5,16 X8,17,9,18 X16,9,17,10 X18,14,1,13
Gauss code 1, -5, 4, -6, 3, -1, 2, -7, 8, -4, 5, -2, 9, -3, 6, -8, 7, -9
Dowker-Thistlethwaite code 6 10 14 12 16 2 18 4 8
Conway Notation [20:20:20]

Three dimensional invariants

Symmetry type Reversible
Unknotting number 2
3-genus 2
Bridge index 3
Super bridge index 4
Nakanishi index 2
Maximal Thurston-Bennequin number [-7][-4]
Hyperbolic Volume 12.0989
A-Polynomial See Data:9 41/A-polynomial

[edit Notes for 9 41's three dimensional invariants]

Four dimensional invariants

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

[edit Notes for 9 41's four dimensional invariants]

Polynomial invariants

Alexander polynomial
Conway polynomial
2nd Alexander ideal (db, data sources)
Determinant and Signature { 49, 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: (0, 1)
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 9 41. Nonzero entries off the critical diagonals (if any exist) are highlighted in red.

\ r
  \  
j \
-6-5-4-3-2-10123χ
7         1-1
5        2 2
3       31 -2
1      52  3
-1     44   0
-3    44    0
-5   34     1
-7  24      -2
-9 13       2
-11 2        -2
-131         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[9, 41]]
Out[2]=  
9
In[3]:=
PD[Knot[9, 41]]
Out[3]=  
PD[X[6, 2, 7, 1], X[12, 8, 13, 7], X[14, 5, 15, 6], X[10, 3, 11, 4], 
 X[2, 11, 3, 12], X[4, 15, 5, 16], X[8, 17, 9, 18], X[16, 9, 17, 10], 

X[18, 14, 1, 13]]
In[4]:=
GaussCode[Knot[9, 41]]
Out[4]=  
GaussCode[1, -5, 4, -6, 3, -1, 2, -7, 8, -4, 5, -2, 9, -3, 6, -8, 7, -9]
In[5]:=
BR[Knot[9, 41]]
Out[5]=  
BR[5, {-1, -1, -2, 1, 3, 2, 2, -4, -3, 2, -3, -4}]
In[6]:=
alex = Alexander[Knot[9, 41]][t]
Out[6]=  
     3    12             2

19 + -- - -- - 12 t + 3 t

     2   t
t
In[7]:=
Conway[Knot[9, 41]][z]
Out[7]=  
       4
1 + 3 z
In[8]:=
Select[AllKnots[], (alex === Alexander[#][t])&]
Out[8]=  
{Knot[9, 41], Knot[11, NonAlternating, 83]}
In[9]:=
{KnotDet[Knot[9, 41]], KnotSignature[Knot[9, 41]]}
Out[9]=  
{49, 0}
In[10]:=
J=Jones[Knot[9, 41]][q]
Out[10]=  
     -6   3    5    7    8    8            2    3

8 + q - -- + -- - -- + -- - - - 5 q + 3 q - q

          5    4    3    2   q
q q q q
In[11]:=
Select[AllKnots[], (J === Jones[#][q] || (J /. q-> 1/q) === Jones[#][q])&]
Out[11]=  
{Knot[9, 41], Knot[11, NonAlternating, 4], Knot[11, NonAlternating, 21]}
In[12]:=
A2Invariant[Knot[9, 41]][q]
Out[12]=  
 -20    -18    2     -12    2    2    2     -2      2      4    6

q + q - --- - q - --- + -- + -- + q + 2 q - 2 q + q +

              16           10    8    4
             q            q     q    q

  8    10
q - q
In[13]:=
Kauffman[Knot[9, 41]][a, z]
Out[13]=  
                                                      2
   2      4    6              3        5        2   z        2  2

-3 a - 3 a - a - 2 a z - 4 a z - 2 a z + 6 z - -- + 17 a z +

                                                     2
                                                    a

                       3      3
     4  2      6  2   z    3 z         3       3  3      5  3
 13 a  z  + 3 a  z  + -- - ---- + 6 a z  + 19 a  z  + 9 a  z  - 
                       3    a
                      a

            4                                      5
     4   3 z        2  4       4  4      6  4   5 z          5
 11 z  + ---- - 23 a  z  - 12 a  z  - 3 a  z  + ---- - 11 a z  - 
           2                                     a
          a

     3  5       5  5      6      2  6    4  6    6  6        7
 26 a  z  - 10 a  z  + 7 z  + 5 a  z  - a  z  + a  z  + 6 a z  + 

    3  7      5  7      2  8      4  8
9 a z + 3 a z + 2 a z + 2 a z
In[14]:=
{Vassiliev[2][Knot[9, 41]], Vassiliev[3][Knot[9, 41]]}
Out[14]=  
{0, 1}
In[15]:=
Kh[Knot[9, 41]][q, t]
Out[15]=  
4           1        2        1       3       2       4       3

- + 5 q + ------ + ------ + ----- + ----- + ----- + ----- + ----- + q 13 6 11 5 9 5 9 4 7 4 7 3 5 3

         q   t    q   t    q  t    q  t    q  t    q  t    q  t

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