Opened 7 months ago

Last modified 4 months ago

#28981 new defect

Bug with dimension for subschemes of products of projective spaces

Reported by: gjorgenson Owned by:
Priority: minor Milestone: sage-9.2
Component: algebraic geometry Keywords:
Cc: Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description

PP.<x,y,z,a,b,c> = ProductProjectiveSpaces(QQ, [2,2])
X = PP.subscheme([x*a, x*b, x*c, y*a, y*b, y*c, z*a, z*b])
print(X.dimension())
print(X.segre_embedding().codomain().dimension())

Here X.dimension() returns 1, while X.segre_embedding().codomain().dimension() returns the correct answer of 0, as this subscheme is supported on a single point.

Change History (2)

comment:1 Changed 7 months ago by gjorgenson

  • Component changed from PLEASE CHANGE to algebraic geometry

comment:2 Changed 4 months ago by mkoeppe

  • Milestone changed from sage-9.1 to sage-9.2

Moving tickets to milestone sage-9.2 based on a review of last modification date, branch status, and severity.

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