#9138: Categories for all rings
--------------------------+-------------------------------------------------
Reporter: jbandlow | Owner: nthiery
Type: defect | Status: needs_review
Priority: major | Milestone: sage-4.7
Component: categories | Keywords: introspection, categories for rings
Work_issues: | Upstream: N/A
Reviewer: | Author: Simon King
Merged: | Dependencies:
--------------------------+-------------------------------------------------
Changes (by SimonKing):
* status: needs_work => needs_review
* work_issues: Categories for more rings... =>
Comment:
The first patch did not cover all rings - it turned out that many classes
derived from sage.rings.ring.Ring do in fact ''not'' call the `__init__`
method of rings. Hence, in these cases, the category stuff was not
present.
The second patch takes care of some of these cases - I think I shouldn't
vouch for completeness, though. Moreover, I implemented the new coercion
model for some more classes of rings, such as free algebras, quotient
rings, and boolean polynomial rings.
Concerning quotient rings: I hope that the category of this quotient ring
is correctly chosen:
{{{
sage: P.<x,y> = QQ[]
sage: Q = P.quo(P*[x^2+y^2])
sage: Q.category()
Join of Category of commutative rings and Category of subquotients of
monoids and Category of quotients of semigroups
}}}
What do you think: Should it perhaps better be "join of Category of
commutative algebras over Rational Field and Category of subquotients
..."? After all, P belongs to the category of commutative algebras over
the rational field.
But apart from that, it seems ready for review now.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9138#comment:52>
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