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feat(Mathlib/RingTheory/TwoSidedIdeal/SpanAsSum): span of set as finsum#23320

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Whysoserioushah wants to merge 14 commits intomasterfrom
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feat(Mathlib/RingTheory/TwoSidedIdeal/SpanAsSum): span of set as finsum#23320
Whysoserioushah wants to merge 14 commits intomasterfrom
span'

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@Whysoserioushah Whysoserioushah commented Mar 25, 2025

co-authored by: @jjaassoonn


splited from #23216 following @eric-wieser advice

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github-actions bot commented Mar 25, 2025

PR summary a40dba502b

Import changes for modified files

No significant changes to the import graph

Import changes for all files
Files Import difference
Mathlib.RingTheory.TwoSidedIdeal.SpanAsSum (new file) 1248

Declarations diff

+ mem_span_ideal_iff_exists_fin
+ mem_span_iff_exists_fin
+ mem_span_range_iff_exists_multisetSum

You can run this locally as follows
## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/declarations_diff.sh long <optional_commit>

The doc-module for script/declarations_diff.sh contains some details about this script.


No changes to technical debt.

You can run this locally as

./scripts/technical-debt-metrics.sh pr_summary
  • The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
  • The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

@github-actions github-actions bot added the t-algebra Algebra (groups, rings, fields, etc) label Mar 25, 2025
Comment on lines +62 to +64
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
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@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?

@Paul-Lez Paul-Lez self-requested a review April 3, 2025 14:02
Whysoserioushah and others added 2 commits April 3, 2025 16:05
Co-authored-by: Paul Lezeau <paul.lezeau@gmail.com>
@Whysoserioushah Whysoserioushah requested a review from b-mehta April 3, 2025 19:24
mathlib-bors bot pushed a commit that referenced this pull request Apr 8, 2025
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>
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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)

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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 :)

tannerduve pushed a commit that referenced this pull request May 13, 2025
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>
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I will close this PR and make a new one from my fork

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4 participants