feat(Mathlib/RingTheory/TwoSidedIdeal/SpanAsSum): span of set as finsum#23320
feat(Mathlib/RingTheory/TwoSidedIdeal/SpanAsSum): span of set as finsum#23320Whysoserioushah wants to merge 14 commits intomasterfrom
Conversation
PR summary a40dba502bImport changes for modified filesNo significant changes to the import graph Import changes for all files
|
| lemma mem_span_range_iff_exists_multisetSum (ι : Type*) (v : ι → R) (x : R) : | ||
| x ∈ span (Set.range v) ↔ ∃ l : Multiset (R × ι × R), | ||
| (l.map fun | (l, i, r) => l * v i * r).sum = x := by |
There was a problem hiding this comment.
@j-loreaux, can you think of a nice statement of this that makes sense for non-unital rings? Perhaps a Multiset (WithOne R × ι × WithOne R) along with a DistribMulAction (WithOne R) R instance for NonUnitalRing R?
Co-authored-by: Paul Lezeau <paul.lezeau@gmail.com>
splitted from #23320 following @eric-wieser advice Co-authored-by: Jujian Zhang <jujian.zhang19@imperial.ac.uk> Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
eric-wieser
left a comment
There was a problem hiding this comment.
It's ultimately not clear to me that this PR is useful, given that we already have TwoSidedIdeal.mem_span_iff_mem_addSubgroup_closure from #14460 (cc @jjaassoonn, @j-loreaux)
this was used to prove wedderburn but since @alreadydone already has several PRs to prove that I would say it's not urgently needed but I'm still going to need this theorem at some point later, when I get there if this PR is still not merged I could make another dependent PR to convince you :) |
splitted from #23320 following @eric-wieser advice Co-authored-by: Jujian Zhang <jujian.zhang19@imperial.ac.uk> Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
|
I will close this PR and make a new one from my fork |
co-authored by: @jjaassoonn
splited from #23216 following @eric-wieser advice