8 12

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8_11

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8_13

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8 12 Quick Notes




In symmetric decorative form

Knot presentations

Planar diagram presentation X4251 X10,8,11,7 X8394 X2,9,3,10 X14,6,15,5 X16,11,1,12 X12,15,13,16 X6,14,7,13
Gauss code 1, -4, 3, -1, 5, -8, 2, -3, 4, -2, 6, -7, 8, -5, 7, -6
Dowker-Thistlethwaite code 4 8 14 10 2 16 6 12
Conway Notation [2222]

Three dimensional invariants

Symmetry type Fully amphicheiral
Unknotting number 2
3-genus 2
Bridge index 2
Super bridge index [math]\displaystyle{ \{4,6\} }[/math]
Nakanishi index 1
Maximal Thurston-Bennequin number [-5][-5]
Hyperbolic Volume 8.93586
A-Polynomial See Data:8 12/A-polynomial

[edit Notes for 8 12'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{ 2 }[/math]
Rasmussen s-Invariant 0

[edit Notes for 8 12's four dimensional invariants]

Polynomial invariants

Alexander polynomial [math]\displaystyle{ t^2-7 t+13-7 t^{-1} + t^{-2} }[/math]
Conway polynomial [math]\displaystyle{ z^4-3 z^2+1 }[/math]
2nd Alexander ideal (db, data sources) [math]\displaystyle{ \{1\} }[/math]
Determinant and Signature { 29, 0 }
Jones polynomial [math]\displaystyle{ q^4-2 q^3+4 q^2-5 q+5-5 q^{-1} +4 q^{-2} -2 q^{-3} + q^{-4} }[/math]
HOMFLY-PT polynomial (db, data sources) [math]\displaystyle{ a^4-2 z^2 a^2-a^2+z^4+z^2+1-2 z^2 a^{-2} - a^{-2} + a^{-4} }[/math]
Kauffman polynomial (db, data sources) [math]\displaystyle{ a z^7+z^7 a^{-1} +2 a^2 z^6+2 z^6 a^{-2} +4 z^6+2 a^3 z^5+2 a z^5+2 z^5 a^{-1} +2 z^5 a^{-3} +a^4 z^4-a^2 z^4-z^4 a^{-2} +z^4 a^{-4} -4 z^4-3 a^3 z^3-3 a z^3-3 z^3 a^{-1} -3 z^3 a^{-3} -2 a^4 z^2-2 a^2 z^2-2 z^2 a^{-2} -2 z^2 a^{-4} +a^3 z+z a^{-3} +a^4+a^2+ a^{-2} + a^{-4} +1 }[/math]
The A2 invariant [math]\displaystyle{ q^{14}+q^{12}-q^{10}+q^8-q^4+q^2-1+ q^{-2} - q^{-4} + q^{-8} - q^{-10} + q^{-12} + q^{-14} }[/math]
The G2 invariant [math]\displaystyle{ q^{66}-q^{64}+3 q^{62}-3 q^{60}+2 q^{58}-3 q^{54}+9 q^{52}-11 q^{50}+12 q^{48}-8 q^{46}+10 q^{42}-17 q^{40}+23 q^{38}-18 q^{36}+8 q^{34}+4 q^{32}-16 q^{30}+17 q^{28}-13 q^{26}+3 q^{24}+6 q^{22}-12 q^{20}+9 q^{18}-12 q^{14}+21 q^{12}-23 q^{10}+15 q^8-q^6-14 q^4+27 q^2-29+27 q^{-2} -14 q^{-4} - q^{-6} +15 q^{-8} -23 q^{-10} +21 q^{-12} -12 q^{-14} +9 q^{-18} -12 q^{-20} +6 q^{-22} +3 q^{-24} -13 q^{-26} +17 q^{-28} -16 q^{-30} +4 q^{-32} +8 q^{-34} -18 q^{-36} +23 q^{-38} -17 q^{-40} +10 q^{-42} -8 q^{-46} +12 q^{-48} -11 q^{-50} +9 q^{-52} -3 q^{-54} +2 q^{-58} -3 q^{-60} +3 q^{-62} - q^{-64} + q^{-66} }[/math]

Vassiliev invariants

V2 and V3: (-3, 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
[math]\displaystyle{ -12 }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ 72 }[/math] [math]\displaystyle{ 82 }[/math] [math]\displaystyle{ 30 }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ -288 }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ -984 }[/math] [math]\displaystyle{ -360 }[/math] [math]\displaystyle{ -\frac{8031}{10} }[/math] [math]\displaystyle{ \frac{1226}{15} }[/math] [math]\displaystyle{ -\frac{9262}{15} }[/math] [math]\displaystyle{ \frac{479}{6} }[/math] [math]\displaystyle{ -\frac{1311}{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]0 is the signature of 8 12. 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      31 2
3     21  -1
1    33   0
-1   33    0
-3  12     -1
-5 13      2
-7 1       -1
-91        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=1 }[/math]
[math]\displaystyle{ r=-4 }[/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}^{3}\oplus{\mathbb Z}_2 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]
[math]\displaystyle{ r=-1 }[/math] [math]\displaystyle{ {\mathbb Z}^{2}\oplus{\mathbb Z}_2^{3} }[/math] [math]\displaystyle{ {\mathbb Z}^{3} }[/math]
[math]\displaystyle{ r=0 }[/math] [math]\displaystyle{ {\mathbb Z}^{3}\oplus{\mathbb Z}_2^{2} }[/math] [math]\displaystyle{ {\mathbb Z}^{3} }[/math]
[math]\displaystyle{ r=1 }[/math] [math]\displaystyle{ {\mathbb Z}^{3}\oplus{\mathbb Z}_2^{2} }[/math] [math]\displaystyle{ {\mathbb Z}^{2} }[/math]
[math]\displaystyle{ r=2 }[/math] [math]\displaystyle{ {\mathbb Z}\oplus{\mathbb Z}_2^{3} }[/math] [math]\displaystyle{ {\mathbb Z}^{3} }[/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 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]

Computer Talk

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

[math]\displaystyle{ \textrm{Include}(\textrm{ColouredJonesM.mhtml}) }[/math]

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

13 + t - - - 7 t + t

t
In[7]:=
Conway[Knot[8, 12]][z]
Out[7]=  
       2    4
1 - 3 z  + z
In[8]:=
Select[AllKnots[], (alex === Alexander[#][t])&]
Out[8]=  
{Knot[8, 12]}
In[9]:=
{KnotDet[Knot[8, 12]], KnotSignature[Knot[8, 12]]}
Out[9]=  
{29, 0}
In[10]:=
J=Jones[Knot[8, 12]][q]
Out[10]=  
     -4   2    4    5            2      3    4

5 + q - -- + -- - - - 5 q + 4 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, 12]}
In[12]:=
A2Invariant[Knot[8, 12]][q]
Out[12]=  
      -14    -12    -10    -8    -4    -2    2    4    8    10    12

-1 + q + q - q + q - q + q + q - q + q - q + q +

  14
q
In[13]:=
Kauffman[Knot[8, 12]][a, z]
Out[13]=  
                                         2      2
    -4    -2    2    4   z     3     2 z    2 z       2  2      4  2

1 + a + a + a + a + -- + a z - ---- - ---- - 2 a z - 2 a z -

                          3            4      2
                         a            a      a

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

    5      5                                6              7
 2 z    2 z         5      3  5      6   2 z       2  6   z       7
 ---- + ---- + 2 a z  + 2 a  z  + 4 z  + ---- + 2 a  z  + -- + a z
   3     a                                 2              a
a a
In[14]:=
{Vassiliev[2][Knot[8, 12]], Vassiliev[3][Knot[8, 12]]}
Out[14]=  
{0, 0}
In[15]:=
Kh[Knot[8, 12]][q, t]
Out[15]=  
3           1       1       1       3       1      2      3

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