Catalog of simplicial sets¶
This provides pre-built simplicial sets:
- the n-sphere and n-dimensional real projective space, both (in theory) for any positive integer n. In practice, as n increases, it takes longer to construct these simplicial sets.
- the n-simplex and the horns obtained from it. As n increases, it
takes much longer to construct these simplicial sets, because the
number of nondegenerate simplices increases exponentially in n.
For example, it is feasible to do
simplicial_sets.RealProjectiveSpace(100)
since it only has 101 nondegenerate simplices, butsimplicial_sets.Simplex(20)
is probably a bad idea. - n-dimensional complex projective space for n≤4
- the classifying space of a finite multiplicative group or monoid
- the torus and the Klein bottle
- the point
- the Hopf map: this is a pre-built morphism, from which one can extract its domain, codomain, mapping cone, etc.
All of these examples are accessible by typing
simplicial_sets.NAME
, where NAME
is the name of the
example. Type simplicial_sets.[TAB]
for a complete list.
EXAMPLES:
sage: RP10 = simplicial_sets.RealProjectiveSpace(8)
sage: RP10.homology()
{0: 0, 1: C2, 2: 0, 3: C2, 4: 0, 5: C2, 6: 0, 7: C2, 8: 0}
sage: eta = simplicial_sets.HopfMap()
sage: S3 = eta.domain()
sage: S2 = eta.codomain()
sage: S3.wedge(S2).homology()
{0: 0, 1: 0, 2: Z, 3: Z}