#17550: sorted variables in multivariate polynomial ring wrong order
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Reporter: dkrenn | Owner:
Type: defect | Status: needs_info
Priority: major | Milestone: sage-duplicate/invalid/wontfix
Component: algebra | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Changes (by dkrenn):
* status: positive_review => needs_info
Comment:
Replying to [comment:2 nbruin]:
> Polynomial rings have a monomial order which should affect how monomials
(and hence terms) compare:
> {{{
> sage: A.<a,b>=PolynomialRing(Rationals(),order="lex")
> sage: sorted([a^i*b^j for i in [0..2] for j in [0..2]])
> [1, b, b^2, a, a*b, a*b^2, a^2, a^2*b, a^2*b^2]
> sage: A.<a,b>=PolynomialRing(Rationals(),order="deglex")
> sage: sorted([a^i*b^j for i in [0..2] for j in [0..2]])
> [1, b, a, b^2, a*b, a^2, a*b^2, a^2*b, a^2*b^2]
> sage: A.<a,b>=PolynomialRing(Rationals(),order="degrevlex")
> sage: sorted([a^i*b^j for i in [0..2] for j in [0..2]])
> [1, b, a, b^2, a*b, a^2, a*b^2, a^2*b, a^2*b^2]
> }}}
I understand that the original posted "problem" is not one, since we use
"degrevlex", but using "lex" or "deglex" the output of the lines above
should definitely start with {{{[1, a, ...]}}}.
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Ticket URL: <http://trac.sagemath.org/ticket/17550#comment:5>
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