Opened 3 years ago

Last modified 3 years ago

#27479 closed defect

Univariate PolynomialRing with 'negdegrevlex' order does not get 'ds' order in Singular — at Version 1

Reported by: rburing Owned by:
Priority: major Milestone: sage-8.8
Component: interfaces Keywords: PolynomialRing, Singular, order
Cc: Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

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Description (last modified by rburing)

Using _singular_init_() univariate polynomial rings get global monomial ordering lp no matter what:

sage: R.<x> = PolynomialRing(QQ, 1, order='negdegrevlex')
sage: R._singular_init_()
polynomial ring, over a field, global ordering
// coefficients: QQ
// number of vars : 1
//        block   1 : ordering lp
//                  : names    x
//        block   2 : ordering C

Contrast with multivariate:

sage: S.<y,z> = PolynomialRing(QQ, 2, order='negdegrevlex')
sage: S._singular_init_()
polynomial ring, over a field, local ordering
// coefficients: QQ
// number of vars : 2
//        block   1 : ordering ds
//                  : names    y z
//        block   2 : ordering C

As long as neg* orders are allowed (see #10708) this should be fixed (and it seems easy to fix).

This is also the cause of a bug in multiplicity() for subschemes of the affine line:

sage: A1.<x> = AffineSpace(QQ,1)
sage: X=A1.subscheme([x^1789+x])
sage: Q=X([0])
sage: X.multiplicity(Q)

Change History (1)

comment:1 Changed 3 years ago by rburing

  • Description modified (diff)
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