isProjective X
A variety is projective if it can be realized as a closed subvariety of some projective space. For an normal toric variety, this is equivalent to saying that the associated fan is the normal fan of a polytope.
Nontrivial affine varieties are not projective.
|
|
|
|
Many of our favour toric varieties are projective.
|
|
|
|
|
There are complete non-projective normal toric varieties.
|
|
|
|
To determine if a normal toric variety is projective, we use the Gale dual vector configuration associated to the rays; see Theorem V.4.8 in Ewald's Combinatorial convexity and algebraic geometry for more information.
To avoid repeating a computation, the package caches the result in the CacheTable of the normal toric variety.