univariate homogenize is not the same as multivariate homogenize

[ncalexan]

Ticket #2349 fixes the multivariate case. This ticket is for the univariate case. Some examples (these work after like this AFTER #2349 has been applied):

sage: x = Zmod(3)['x'].0; (x^2 + x).homogenize()
---------------------------------------------------------------------------
<type 'exceptions.AttributeError'>        Traceback (most recent call last)

/Users/ncalexan/<ipython console> in <module>()

<type 'exceptions.AttributeError'>: 'sage.rings.polynomial.polynomial_modn_dense_ntl.Po' object has no attribute 'homogenize'
sage: x = PolynomialRing(Zmod(3), 1, 'x').0; (x^2 + x).homogenize()
x^2 + x*h
sage: x = GF(3)['x'].0; (x^2 + x).homogenize()
---------------------------------------------------------------------------
<type 'exceptions.AttributeError'>        Traceback (most recent call last)

/Users/ncalexan/<ipython console> in <module>()

<type 'exceptions.AttributeError'>: 'sage.rings.polynomial.polynomial_modn_dense_ntl.Po' object has no attribute 'homogenize'
sage: x = PolynomialRing(GF(3), 1, 'x').0; (x^2 + x).homogenize()
x^2 + x*h

CC: @ncalexan

Component: commutative algebra

Keywords: univariate polynomial homogenize

Author: Luis Felipe Tabera Alonso, Julian Rueth

Branch/Commit: 03bf755

Reviewer: Julian Rueth, Luis Felipe Tabera Alonso

Issue created by migration from https://trac.sagemath.org/ticket/2352

[lftabera]

Author: Luis Felipe Tabera Alonso

[lftabera]

comment:5

One step more to unify some methods of univariate and multivariate polynomials.

---

New commits:

e5599ea

Ticket 2352: univariate homogenize

[lftabera]

Branch: u/lftabera/ticket/2352-homogenize-univariate

[lftabera]

Commit: e5599ea

[saraedum]

comment:6

Should (1+t).homogenize('t') really be zero? The docstring says that setting this variable to one yields the original polynomial which does not seem to be the case. So should we clarify (also in the multivariate case) that strange things may happen if var is a variable which appears in the polynomial?

[saraedum]

Changed branch from u/lftabera/ticket/2352-homogenize-univariate to u/saraedum/ticket/2352

[saraedum]

Changed commit from e5599ea to 03bf755

[saraedum]

Reviewer: Julian Rueth

[saraedum]

Changed author from Luis Felipe Tabera Alonso to Luis Felipe Tabera Alonso, Julian Rueth

[saraedum]

comment:10

I tried to clarify the behaviour in the docstrings. I hope you do not mind my changes.

---

New commits:

03bf755

Improved docstrings of homogenize() of polynomials

[lftabera]

comment:11

Thanks, the documentation has improved, much clearer now.

[lftabera]

Changed reviewer from Julian Rueth to Julian Rueth, Luis Felipe Tabera Alonso

[vbraun]

Changed branch from u/saraedum/ticket/2352 to 03bf755