Opened 12 years ago

Closed 12 years ago

## #10676 closed defect (duplicate)

# [duplicate] Bizarre results for genus of a singular curve

Reported by: | David Loeffler | Owned by: | Alex Ghitza |
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Priority: | major | Milestone: | sage-duplicate/invalid/wontfix |

Component: | algebraic geometry | Keywords: | |

Cc: | Merged in: | ||

Authors: | Reviewers: | David Loeffler | |

Report Upstream: | N/A | Work issues: | |

Branch: | Commit: | ||

Dependencies: | Stopgaps: |

### Description

In vanilla Sage 4.6.1:

sage: R.<x, y, z> = QQ[] sage: C = Curve(x^2 - 2*y^2) sage: C.is_singular() True sage: C.genus() 4294967295

I'm not quite sure how one defines the genus of a reducible variety, but I'm pretty sure that answer's not right...

(I spotted this during testing #727, but it has nothing to do with conics, of course.)

### Change History (4)

### comment:1 Changed 12 years ago by

### comment:2 Changed 12 years ago by

Milestone: | sage-4.6.2 → sage-duplicate/invalid/wontfix |
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Status: | new → needs_review |

Summary: | Bizarre results for genus of a singular curve → [duplicate] Bizarre results for genus of a singular curve |

So it is. Release manager: please close.

### comment:3 Changed 12 years ago by

Status: | needs_review → positive_review |
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### comment:4 Changed 12 years ago by

Resolution: | → duplicate |
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Reviewers: | → David Loeffler |

Status: | positive_review → closed |

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This is a duplicate of #10308