Lightly Documented Features: Difference between revisions

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n = 4 |
n = 4 |
in = <nowiki>Total[AlternatingQ /@ AllKnots[{0,11}]]</nowiki> |
in = <nowiki>Total[AlternatingQ /@ AllKnots[{0,11}]]</nowiki> |
out= <nowiki>239 False + 563 True</nowiki>}}
out= <nowiki>238 False + 564 True</nowiki>}}
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Revision as of 21:04, 12 December 2007


(For In[1] see Setup)

In[1]:= ?NumberOfKnots
NumberOfKnots[n] returns the number of knots with n crossings. NumberOfKnots[n, Alternating|NonAlternating] returns the number of knots of the specified type.
In[2]:= NumberOfKnots[16, NonAlternating]
Out[2]= 1008906
In[3]:= ?AlternatingQ
AlternatingQ[D] returns True iff the knot/link diagram D is alternating.

Among the knots with up to 11 crossings, 564 are alternating and 238 are not:

In[4]:= Total[AlternatingQ /@ AllKnots[{0,11}]]
Out[4]= 238 False + 564 True