#13229: Adding `DegNegLex` to TermOrder
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Reporter: AlexanderDreyer |
Owner: AlexanderDreyer
Type: enhancement |
Status: needs_review
Priority: major |
Milestone: sage-5.3
Component: commutative algebra |
Resolution:
Keywords: | Work
issues:
Report Upstream: None of the above - read trac for reasoning. |
Reviewers:
Authors: Alexander Dreyer | Merged
in:
Dependencies: |
Stopgaps:
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Description changed by AlexanderDreyer:
Old description:
> The attached patch adds the Degree Negative Lexicographical term order
> (`DegNegLex`) to Sage 5.1.
>
> It is defined as follows: x^**a**^ < x^**b**^ if and only if
> deg(x^**a**^) < deg(x^**b**^) or deg(x^**a**^) = deg(x^**b**^) and there
> exists 1 <= i <= n such that a,,1,, = b,, 1,, , ... , a,, i-1,, = b,,
> i-1,,, ..., a,,i,, > b,,i,,.
>
> It is a native term ordering of `PolyBoRi` ("`dp_asc`") which Sage does
> not support yet. But Sage uses it internally to implement
> `DegRevLex`-ordered `BooleanPolynomialRing`s by reverting `.gens()`. It
> is useful for Sage to distinguish between the original `dp_asc` and
> `DegRevLex`. It will help to fix some design issues discovered when
> fixing #13202.
>
> Singular supports this as `(a(1:n),rp(n))`. The patch also includes the
> patches for the interfaces `libSingular` and Singular-pexpect.
>
> * '''Apply:''' [attachment:degneglex.patch]
New description:
The attached patch adds the Degree Negative Lexicographical term order
(`DegNegLex`) to Sage 5.1.
It is defined as follows: x^**a**^ < x^**b**^ if and only if deg(x^**a**^)
< deg(x^**b**^) or deg(x^**a**^) = deg(x^**b**^) and there exists 1 <= i
<= n such that a,,1,, = b,, 1,, , ... , a,, i-1,, = b,, i-1,,, ...,
a,,i,, > b,,i,,.
It is a native term ordering of `PolyBoRi` ("`dp_asc`") which Sage does
not support yet. But Sage uses it internally to implement
`DegRevLex`-ordered `BooleanPolynomialRing`s by reverting `.gens()`. It
is useful for Sage to distinguish between the original `dp_asc` and
`DegRevLex`. It will help to fix some design issues discovered when fixing
#13202.
Singular supports this as `(a(1:n),ls(n))`. The patch also includes the
patches for the interfaces `libSingular` and Singular-pexpect.
* '''Apply:''' [attachment:degneglex.patch]
--
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13229#comment:8>
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