Finite Type (Vassiliev) Invariants: Difference between revisions

From Knot Atlas
Jump to navigationJump to search
No edit summary
No edit summary
Line 4: Line 4:


<!--$$?Vassiliev$$-->
<!--$$?Vassiliev$$-->
<!--Robot Land, no human edits to "END"-->
{{Help1|n=1|s=Vassiliev}}
Vassiliev[2][K] computes the (standardly normalized) type 2 Vassiliev invariant of the knot K, i.e., the coefficient of z^2 in Conway[K][z]. Vassiliev[3][K] computes the (standardly normalized) type 3 Vassiliev invariant of the knot K, i.e., 3J''(1)-(1/36)J'''(1) where J is the Jones polynomial of K.
{{Help2}}
<!--END-->
<!--END-->


Line 16: Line 20:
PlotStyle -> PointSize[0.02], PlotRange -> All, AspectRatio -> 1
PlotStyle -> PointSize[0.02], PlotRange -> All, AspectRatio -> 1
]$$-->
]$$-->
<!--Robot Land, no human edits to "END"-->
{{Graphics1|n=2}}
Show[ot[
Join @@ Table[
K = Knot[10, k] ; v2 = Vassiliev[2][K]; v3 = Vassiliev[3][K];
{{v2, v3}, {v2, -v3}},
{k, 165}
],
PlotStyle -> PointSize[0.02], PlotRange -> All, AspectRatio -> 1]
{{Graphics2|n=2|imagename=Finite_Type_%28Vassiliev%29_Invariants_Out_2.gif}}
<!--END-->
<!--END-->

Revision as of 22:43, 28 August 2005


(For In[1] see Setup)

In[1]:= ?Vassiliev

Vassiliev[2][K] computes the (standardly normalized) type 2 Vassiliev invariant of the knot K, i.e., the coefficient of z^2 in Conway[K][z]. Vassiliev[3][K] computes the (standardly normalized) type 3 Vassiliev invariant of the knot K, i.e., 3J(1)-(1/36)J'(1) where J is the Jones polynomial of K.

Thus, for example, let us reproduce Willerton's "fish" (arXiv:math.GT/0104061), the result of plotting the values of against the values of , where is the (standardly normalized) type 2 invariant of , is the (standardly normalized) type 3 invariant of , and where runs over a set of knots with equal crossing numbers (10, in the example below):

In[2]:=

Show[ot[

 Join @@ Table[
   K = Knot[10, k] ; v2 = Vassiliev[2][K]; v3 = Vassiliev[3][K];
   {{v2, v3}, {v2, -v3}},
   {k, 165}
 ],
 PlotStyle -> PointSize[0.02], PlotRange -> All, AspectRatio -> 1]
File:Finite Type (Vassiliev) Invariants Out 2.gif
Out[2]= -Graphics-