#9138: Categories for all rings
---------------------------------+------------------------------------------
Reporter: jbandlow | Owner: nthiery
Type: defect | Status: needs_work
Priority: major | Milestone: sage-4.7.1
Component: categories | Keywords: introspection, categories
for rings
Work_issues: Steenrod algebras | Upstream: N/A
Reviewer: | Author: Simon King
Merged: | Dependencies: sage-4.7, #11268, #11139,
#9976, #9944, #11269
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Comment(by SimonKing):
By inserting print statements into my new init_extra method, I found out
that when it is called, the "one" of the Steenrod algebra is not
available, yet. Therefore, the generic method ("multiply the given element
of the base ring with the multiplicative unit of the algebra") is not
available at that time.
Without my patch, a different method is used for coercion, namely
{{{
SetMorphism(function = self.from_base_ring, parent = Hom(self.base_ring(),
self, Rings()))
}}}
The reason for changing it was the fact that normally
`self.one()._lmul_(r)` is a pretty fast way to convert a base ring element
r into self. But I guess that the old `from_base_ring` should be used if
the unit is not available during initialisation.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9138#comment:73>
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