Zulip Chat Archive
Stream: maths
Topic: name of ring hom associated to function
Kevin Buzzard (May 28 2020 at 15:26):
of_real
is the function from to . The bundled ring hom will hence have to be called something else. What should it be called? Of_real
? Same question for complex.conj
Johan Commelin (May 28 2020 at 15:35):
We've been using the ugly _hom
suffix, or a l
, a
, r
prefix for "linear", "alg_hom", or "ring_hom".
Johan Commelin (May 28 2020 at 15:35):
I don't like any of these
Johan Commelin (May 28 2020 at 15:36):
Now that inferring arguments of bundled homs has been fixed (last week, thanks Gabriel :tada:), I think of_real
should be the ring hom, and of_real'
the underlying function.
Mario Carneiro (May 28 2020 at 16:37):
I'm not sure I like that idea. There are lots of homs that a function could be, but only one base function, so it makes sense to give the base function the "preferred" name. Plus, usually the base function comes up more often in statements than the hom, unless you set things up so that the coerced hom is the name of the base function (which only works if there is only one hom you can build over a function). of_real
might be a bit special in this regard because it will usually be referred to via coe
Johan Commelin (May 28 2020 at 16:40):
I would like mv_polynomial.map
to return a ring_hom
instead of a function. I don't want to use mv_polynomial.map_hom
.
Johan Commelin (May 28 2020 at 16:41):
I think int.cast_ring_hom R
is an ugly mouthful for an "invisible" map
Yury G. Kudryashov (May 29 2020 at 05:02):
I think that of_real
should be an alg_hom
while coe
should be defined without of_real
.
Last updated: Dec 20 2023 at 11:08 UTC