Can the star of a ray of a fan be computed in sage?
Let p
be a ray of a fan F
in a lattice N
. Let Np
be the quotient lattice N / N.span(p)
. The star of p
is the fan in Np
defined by
Star(p) = {bar(sigma) | p <= sigma}
(This definition is taken from Definition 4.4 on page 55 of this paper. Is there an algorithm to compute Star(p)
in sage
? If so, what about the embedding morphism Star(p) --> F
?