#20511: Not all empty schemes are created equal
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Reporter: kedlaya | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-7.2
Component: algebraic geometry | Keywords: schemes, empty
Merged in: | Authors:
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Commit: | Dependencies:
Stopgaps: |
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In this example, both schemes are empty, so they should be equal as
subschemes of P^2. However...
{{{
sage: P2.<x,y,z> = ProjectiveSpace(2, QQ)
sage: P2.subscheme([x,y^2,z]) == P2.subscheme([x,y,z])
False
}}}
While I'm at it, an `is_empty` method would be nice. It could be defined
as follows:
{{{
def self.is_empty():
return (len(self.irreducible_components() == 0)
}}}
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Ticket URL: <http://trac.sagemath.org/ticket/20511>
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