projective automorphism group fails for homogenized maps

[bhutz]

When the numerator is a constant, the .polynomial() conversion returns a different variable than the denominator. This is the expected behavior from the documentation of those functions. So this ticket will change how the conversion is done.

Example that fails

A.<z>=AffineSpace(QQ,1)
HA=End(A)
f=HA([1/z^7])
F=f.homogenize(1)
F.automorphism_group()

Component: algebraic geometry

Keywords: projective morphism

Author: Ben Hutz

Branch: 62ce7b2

Reviewer: Grayson Jorgenson

Issue created by migration from https://trac.sagemath.org/ticket/18399

[bhutz]

Branch: u/bhutz/ticket/18399

[bhutz]

New commits:

6c04c13

18399: fix bug in projective morphism automorphism group

[bhutz]

Commit: 6c04c13

[sagetrac-gjorgenson]

comment:3

Everything looks good, but I think the ticket example should be added to the documentation as a test or example to demonstrate the fix.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

62ce7b2

18399: example added

[sagetrac-git]

Changed commit from 6c04c13 to 62ce7b2

[sagetrac-gjorgenson]

Reviewer: Grayson Jorgenson

[vbraun]

Changed branch from u/bhutz/ticket/18399 to 62ce7b2

[bhutz]

Changed commit from 62ce7b2 to none