Currently, EllipticCurve_generic.automorphisms() returns the automorphisms in a more or less arbitrary (albeit deterministic) order.

It is much more natural to users to receive a list with the identity and negation first, since they exist for any curve, then any other automorphisms that may exist. (I have personally seen code making this incorrect assumption.)

In this patch, we change ._comparison_impl() for WeierstrassIsomorphism in such a way that [1] and [-1] will appear first in a sorted list of automorphisms.

Diff without the dependencies: sagemath/sagetrac-mirror@d92c9f4...c9e9646

Depends on #34727
Depends on #34722

CC: @JohnCremona

Component: elliptic curves

Author: Lorenz Panny

Branch/Commit: c9e9646

Reviewer: John Cremona

Issue created by migration from https://trac.sagemath.org/ticket/34728