Opened 16 months ago

Last modified 3 weeks ago

#28981 new defect

Fix dimension for subscheme of product of projective spaces

Reported by: gjorgenson Owned by:
Priority: minor Milestone: sage-9.4
Component: algebraic geometry Keywords: subscheme
Cc: Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

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Description (last modified by slelievre)

In Sage 9.3.rc0:

sage: PP.<x, y, z, a, b, c> = ProductProjectiveSpaces(QQ, [2, 2])
sage: X = PP.subscheme([x*a, x*b, x*c, y*a, y*b, y*c, z*a, z*b])
sage: X.dimension()  # expected: 0
1
sage: X.segre_embedding().codomain().dimension()  # correct
0

The answer returned by X.segre_embedding().codomain().dimension() is correct, as this subscheme is supported on a single point.

The answer returned by X.dimension() is incorrect.

Change History (5)

comment:1 Changed 16 months ago by gjorgenson

  • Component changed from PLEASE CHANGE to algebraic geometry

comment:2 Changed 12 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.

comment:3 Changed 7 months ago by mkoeppe

  • Milestone changed from sage-9.2 to sage-9.3

comment:4 Changed 6 weeks ago by slelievre

  • Description modified (diff)
  • Keywords subscheme added
  • Summary changed from Bug with dimension for subschemes of products of projective spaces to Fix dimension for subscheme of product of projective spaces

comment:5 Changed 3 weeks ago by mkoeppe

  • Milestone changed from sage-9.3 to sage-9.4
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