Make FiniteRankFreeModule.tensor_module(0, 1) return the dual

[egourgoulhon]

In Sage 9.7.rc0, we have

sage: M = FiniteRankFreeModule(ZZ, 2, name='M')
sage: M.tensor_module(0, 1) is M.dual()
False

The identity of the two objects, which is mathematically exact, is implemented here. This also simplifies some coercion maps.

CC: @mkoeppe @tscrim @mjungmath

Component: linear algebra

Keywords: tensor_module

Author: Eric Gourgoulhon

Branch/Commit: 803f7e4

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/34474

[egourgoulhon]

Branch: public/manifolds/tensor_module_dual-34474

[egourgoulhon]

Commit: 803f7e4

[egourgoulhon]

New commits:

803f7e4

Make FiniteRankFreeModule.tensor_module(0, 1) return the dual (#34474)

[mkoeppe]

Reviewer: Matthias Koeppe

[mkoeppe]

comment:2

LGTM and passes all tests.

Possible follow-up - #30241

[egourgoulhon]

comment:3

Thanks for the review!

[vbraun]

Changed branch from public/manifolds/tensor_module_dual-34474 to 803f7e4