ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Wed, 11 Apr 2018 13:14:13 +0200connected sum of knotshttps://ask.sagemath.org/question/41985/connected-sum-of-knots/ Hi! I was trying to recursively construct connected sums of knots, but I seem to run in to some problems when connect summing a knot to itself more than two times:
>B = BraidGroup(2)
>trefoil = Knot(B([1,1,1]))
>K = trefoil.connected_sum(trefoil)
>L = K.connected_sum(trefoil)
This does not work:
> ValueError Traceback (most recent call last)
> ipython-input-1-7b977cf99468 in module()
> 2 trefoil = Knot(B([Integer(1),Integer(1),Integer(1)]))
> 3 K = trefoil.connected_sum(trefoil)
> --> 4 L = K.connected_sum(trefoil)
> /home/sc_serv/sage/local/lib/python2.7/site-packages/sage/knots/knot.pyc in connected_sum(self, other)
> 294 return Knot(B(list(b1.Tietze())
> 295 + [(abs(i) + b2s) * Integer(i).sign() for i in b2.Tietze()]
> --> 296 + [b1s]))
> 297
> /home/sc_serv/sage/local/lib/python2.7/site-packages/sage/knots/knot.pyc in __init__(self, data, check)
> 104 if check:
> 105 if self.number_of_components() != 1:
> --> 106 raise ValueError("the input has more than 1 connected component")
> 107
> 108 def __repr__(self):
> ValueError: the input has more than 1 connected component
Am I doing something wrong here?
Thanks in advance!danieleCWed, 11 Apr 2018 13:14:13 +0200https://ask.sagemath.org/question/41985/