Opened 5 years ago

Last modified 5 years ago

#24093 new enhancement

Cannot compute Gröbner fan when ring variables contain each other as prefixes

Reported by: Caitlin Lienkaemper Owned by:
Priority: major Milestone: sage-8.1
Component: commutative algebra Keywords: Gröbner basis, Gröbner fan, gfan, sd90
Cc: Merged in:
Authors: Caitlin Lienkaemper Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

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Description

Trying to compute a Gröbner fan over a ring in which one variable name contains the other as a prefix gives the following error:

sage: P = PolynomialRing(QQ,3*5,"x"); x = P.gens(); M = Matrix(3,x)
sage: M
[ x0  x1  x2  x3  x4]
[ x5  x6  x7  x8  x9]
[x10 x11 x12 x13 x14]
sage: I = P.ideal(M.minors(2))
sage: I.groebner_fan()
---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
...
RuntimeError: Ring variables cannot contain each other as prefixes 

This was brought up in comments on ticket #20146 (now closed), but doesn't seem to have its own ticket.

Change History (2)

comment:1 Changed 5 years ago by Caitlin Lienkaemper

Keywords: sd90 added

comment:2 Changed 5 years ago by Frédéric Chapoton

Minimal case:

sage: R = PolynomialRing(QQ, 'x1,x11')
sage: I = R.ideal(R.gens())
sage: I.groebner_fan()
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