Can't construct fraction field

[jmbr]

----------------------------------------------------------------------
| Sage Version 3.4.2, Release Date: 2009-05-04                       |
| Type notebook() for the GUI, and license() for information.        |
----------------------------------------------------------------------
sage: R.<x, y> = PolynomialRing(QQ, 2) 
sage: I = (x^2 + y^2 - 1)*R
sage: Q = R.quotient(I); Q
Quotient of Multivariate Polynomial Ring in x, y over Rational Field by the ideal (x^2 + y^2 - 1)
sage: Q.fraction_field()
---------------------------------------------------------------------------
NotImplementedError                       Traceback (most recent call last)
<SNIP>

Apply

• attachment: trac_5982-ncalexan-with-check2.patch

• attachment: trac_5982-reviewer.patch

• attachment: trac_5982_review2.patch

CC: @malb

Component: algebra

Author: Nick Alexander, Juan M. Bello Rivas

Reviewer: William Stein, Mike Hansen, Marco Streng

Merged: sage-4.7.1.alpha0

Issue created by migration from https://trac.sagemath.org/ticket/5982

[jmbr]

Description changed:

--- 
+++ 
@@ -1,15 +1,16 @@
----
+
+```
+----------------------------------------------------------------------
 | Sage Version 3.4, Release Date: 2009-03-11 | | Type notebook() for
 the GUI, and license() for information.  |
-
----
+----------------------------------------------------------------------
 
 sage: R.<x, y> = PolynomialRing(QQ, 2) sage: I = (x^2 + y^2 - 1)*R
 sage: Q = R.quotient(I) sage: Q Quotient of Multivariate Polynomial
 Ring in x, y over Rational Field by the ideal (x^2 + y^2 - 1) sage:
 Q.fraction_field()
-
----
+---------------------------------------------------------------------------
 NotImplementedError Traceback (most recent call last)
 
 ...
+```

[jmbr]

Attachment: sage+multi-polynomial-fraction-fields2.diff.gz

Fix/workaround using Macaulay 2

[jmbr]

comment:2

[with patch, needs review]

----------------------------------------------------------------------
| Sage Version 3.4, Release Date: 2009-03-11 | | Type notebook() for
the GUI, and license() for information.  |
----------------------------------------------------------------------

sage: R.<x, y> = PolynomialRing(QQ, 2) sage: I = (x^2 + y^2 - 1)*R
sage: Q = R.quotient(I) sage: Q Quotient of Multivariate Polynomial
Ring in x, y over Rational Field by the ideal (x^2 + y^2 - 1) sage:
Q.fraction_field()
---------------------------------------------------------------------------
NotImplementedError Traceback (most recent call last)

...

[sagetrac-mabshoff]

comment:4

Hi,

M2 isn't a default part of Sage, so the doctest must be made optional. I also don't see a reason why this cannot be implemented via libSingular for example, but maybe I am overlooking things.

You also posted a diff, so please check in the code and post an hg patch to properly preserve credit.

And since you are not listed at http://trac.sagemath.org/sage_trac/wiki please add yourself there.

Cheers,

Michael

[sagetrac-mabshoff]

Description changed:

--- 
+++ 
@@ -5,10 +5,11 @@
 the GUI, and license() for information.  |
 ----------------------------------------------------------------------
 
-sage: R.<x, y> = PolynomialRing(QQ, 2) sage: I = (x^2 + y^2 - 1)*R
-sage: Q = R.quotient(I) sage: Q Quotient of Multivariate Polynomial
-Ring in x, y over Rational Field by the ideal (x^2 + y^2 - 1) sage:
-Q.fraction_field()
+sage: R.<x, y> = PolynomialRing(QQ, 2) 
+sage: I = (x^2 + y^2 - 1)*R
+sage: Q = R.quotient(I) 
+Q Quotient of Multivariate Polynomial Ring in x, y over Rational Field by the ideal (x^2 + y^2 - 1) 
+sage: Q.fraction_field()
 ---------------------------------------------------------------------------
 NotImplementedError Traceback (most recent call last)
 

[sagetrac-mabshoff]

Description changed:

--- 
+++ 
@@ -1,17 +1,15 @@
 
 ```
 ----------------------------------------------------------------------
-| Sage Version 3.4, Release Date: 2009-03-11 | | Type notebook() for
-the GUI, and license() for information.  |
+| Sage Version 3.4.2, Release Date: 2009-05-04                       |
+| Type notebook() for the GUI, and license() for information.        |
 ----------------------------------------------------------------------
-
 sage: R.<x, y> = PolynomialRing(QQ, 2) 
 sage: I = (x^2 + y^2 - 1)*R
-sage: Q = R.quotient(I) 
-Q Quotient of Multivariate Polynomial Ring in x, y over Rational Field by the ideal (x^2 + y^2 - 1) 
+sage: Q = R.quotient(I); Q
+Quotient of Multivariate Polynomial Ring in x, y over Rational Field by the ideal (x^2 + y^2 - 1)
 sage: Q.fraction_field()
 ---------------------------------------------------------------------------
-NotImplementedError Traceback (most recent call last)
-
-...
+NotImplementedError                       Traceback (most recent call last)
+<SNIP>
 ```