I am working with simplicial sets in sagemath. I see a fundamental_group() method in the documentation, but it doesn't seem to work for my simplicial set:
from sage.topology.simplicial_set import *
a = AbstractSimplex(0, name='a')
b = AbstractSimplex(0, name='b')
e = AbstractSimplex(1, name='e')
f = AbstractSimplex(1, name='f')
S = SimplicialSet({e:(a,b), f:(b,a)})
S.homology() # this works
S.fundamental_group() # this doesn't work
(sorry not enough karma for a sagecell link)
The fundamental_group() method seems to work fine if I use the built-in example, like:
S = simplicial_sets.Sphere(1)
Is this method not supported on simplicial sets that are built "by hand"?
(My actual goal is to use a specific complicated example that I built by-hand, so I can't just use the built-in examples.
