I'm not sure if Sage can always tell, if you multiply an element of a
subgroup by an element of the larger group, that the result should make
sense and lie in the larger group. You should be able to fix this by
forcing Sage to consider the subgroup element as lying in the larger group:
rather t
> use
> S4(S4.subgroups()[19][1]) * S4[1]
>
Thank you. That makes perfect sense.
This does not bother me anymore since I found that pre-casting all
subgroup-elements to S4 accelerates my work a lot.
(i.e. S4subgroups=[ [S4(h) for h in H] for H in S4.subgroups()] )
But it is still interest
Dear Hsin-Po Wang,
On 2018-01-30, Hsin-Po Wang wrote:
> But it is still interesting to see if this is an unintentional bug in, say,
> the coercion model and can be fixed.
We have
sage: S4.has_coerce_map_from(S4.subgroups()[19])
True
Hence, the coercion model is supposed to *automatically*
PS:
On 2018-01-30, Simon King wrote:
> The coercion model chooses coercion to the left factor's parent, if
> there are coercions available in *both* directions. However, if there
> only is a coercion from the left factor's parent to the right factor's
> parent but not vice versa, that coercion is