Zulip Chat Archive
Stream: Is there code for X?
Topic: multiset equivalent of is_absolute_value.abv_sum
Xavier Roblot (Jun 04 2022 at 07:36):
I am looking for the multiset
equivalent of docs#is_absolute_value.abv_sum. Something like:
lemma multiset.is_absolute_value.abv_sum {ι : Type*} {S : Type*} {T : Type*} [semiring T]
[ordered_semiring S] (abv : T → S) [is_absolute_value abv] (f : ι → T) (s : multiset ι) :
abv (multiset.map f s).sum ≤ (multiset.map (abv ∘ f) s).sum :=
begin
sorry,
end
It would be also convenient for me to have an equivalent of docs#is_absolute_value.map_prod:
lemma multiset.is_absolute_value.abv.map_prod {ι : Type*} {S : Type*} {T : Type*}
[comm_semiring T] [comm_semiring S] [ordered_semiring S] (abv : T → S) [is_absolute_value abv]
(s : multiset ι) (f : ι → T) :
abv (multiset.map f s).prod = (multiset.map (abv ∘ f) s).prod :=
begin
sorry,
end
I should be able to prove these but I thought they might exist already or maybe there is an easy way to deduce them from the finset
versions that I don't know about
Riccardo Brasca (Jun 04 2022 at 08:31):
If you have a normed space these results can be there for the norm (but I didn't check)
Xavier Roblot (Jun 04 2022 at 12:52):
That's a good idea, but I don't think it's there. I guess I'll just do my own versions
Last updated: Dec 20 2023 at 11:08 UTC