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feat(ErdosProblems): 254#2324

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danielchin wants to merge 27 commits intogoogle-deepmind:mainfrom
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feat(ErdosProblems): 254#2324
danielchin wants to merge 27 commits intogoogle-deepmind:mainfrom
danielchin:erdos-254

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Closes #444

Formalizes Erdos Problem 254: https://www.erdosproblems.com/254

Assisted by Gemini/Antigravity

@github-actions github-actions bot added the erdos-problems Erdős Problems label Feb 16, 2026
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Thanks, looks good, just some minor comments

danielchin and others added 16 commits February 23, 2026 17:57
…epmind#2299)

Map 'solved (Lean)', 'proved (Lean)', 'disproved (Lean)' to 'formally
solved' as a distinct category from 'solved', and tags the issue
"formalisation exists elsewhere".
Resolves google-deepmind#199.

Note: I'm using Claude + Opus for supervised formalization tasks. Claude
has no permission to use git on my machine.

---------

Co-authored-by: Moritz Firsching <firsching@google.com>
Fixes google-deepmind#1828

This PR formalizes Gourevitch's series identity.

Statement:
∑' n, ((1 + 14 n + 76 n^2 + 168 n^3) / 2^(20 n)) * (Nat.centralBinom
n)^7
  = 32 / π^3

Details:
- Adds theorem `gourevitch_series_identity`
- Uses `Nat.centralBinom` for binomial coefficient formulation
- Categorized under `research solved` and `AMS 11 33`
- Includes literature references

References:
- Guillera (2003), Experimental Mathematics
- Au (2025), Journal of Symbolic Computation

---------

Co-authored-by: Felix Pernegger <s59fpern@uni-bonn.de>
Co-authored-by: Paul Lezeau <paul.lezeau@gmail.com>
The `=` should be an `≤` because "eventually zero" should be a
possibility. See also [Thomas Bloom's
comment](https://www.erdosproblems.com/forum/thread/943#post-2158)
…ind#2325)

Went through all of these by hand and updated them accordingly. This was
one of those PRs where half way through, I realize it might have been
better to split it up individually. Let me know if you want me to break
these into smaller PRs for the sake of reviewability.

All these fall into a category:
1) Some of these were actually solved and I've changed the status of
them.
2) Some of these do not have a theorem labeled `erdos_{number}` due to
poor naming convetion.
3) Some of these purposely do not have a theorem labeled
`erdos_{number}` because the original problem was stated in multiple
parts and the parts of the questions are labeled as
`erdos_{number}.parts.i` which are not caught by the py script.
4) Some of these are trying to formalize problems in the form of
`Estimate f(n)`, which doesn't seem to have an agreed upon standard
right now. Some examples of these are problems 1084, 1085, and 1095.
Maybe we can come up with an agreement on how to formalize these?
Possibly defining a lower bound, upper bound, and an equality?

Problem 851 is interesting because it's marked as Proved but is still
red, so I'm not sure what the current status of that one is and left
that as is.

I've also taken the liberty to update references and docstrings to
better match the Erdos Problem website.

Closes google-deepmind#2300 
Closes google-deepmind#2301 
Closes google-deepmind#2302 
Closes google-deepmind#2303 
Closes google-deepmind#2304 
Closes google-deepmind#2305 
Closes google-deepmind#2306 
Closes google-deepmind#2307 
Closes google-deepmind#2308 
Closes google-deepmind#2309 
Closes google-deepmind#2310 
Closes google-deepmind#2311 
Closes google-deepmind#2312 
Closes google-deepmind#2313 
Closes google-deepmind#2314 
Closes google-deepmind#2315 
Closes google-deepmind#2316 
Closes google-deepmind#2317 
Closes google-deepmind#2318 
Closes google-deepmind#2319 
Closes google-deepmind#2320 
Closes google-deepmind#2321 
Closes google-deepmind#2322
@github-actions github-actions bot added linter mathoverflow arxiv wikipedia green-problems Problems from https://people.maths.ox.ac.uk/greenbj/papers/open-problems.pdf oeis Conjectures from oeis.org labels Feb 24, 2026
YaelDillies and others added 5 commits February 23, 2026 18:11
Originally done in google-deepmind#1371.

Co-authored-by: Bolton Bailey <bolton.bailey@gmail.com>
# Description
Let $A_1, \dots, A_{100}$ be ‘cubes’ in $\mathbb{F}^n_3$. Is it true
that $A_1 + \dots + A_{100} = \mathbb{F}^n_3$?

- Closes google-deepmind#1561 

# Testing
- Builds successfully
```shell
$ lake build FormalConjectures/GreensOpenProblems/26.lean 
Build completed successfully (7975 jobs).
```
Website now contains the condition that the set $A$ is pairwise coprime.
If not then there are always infinitely many unrepresentable numbers
(the non-multiples of the gcd).
smmercuri and others added 5 commits February 23, 2026 18:13
- Fix order of quantifiers in Selfridge example because the length `k`
of the sequence is determined by the magnitude of the primes. If we take
`k = 1` before the primes themselves, then very large primes will never
straddle `1` in their sums of reciprocals, giving a contradiction.
- Redefine `consecutivePrimes` in order to formalise this
interpretation.
- The condition that `A` is the set of numbers with only one prime from
the sequence dividing it requires multiplicity one as well.
- Fix constraints on `eps`
- Add a TODO since the updated website mentions that repetitions may be
allowed in `Set.IsMulCardSet`, although both versions are open.
fixes google-deepmind#1975 

Assisted by Claude Opus 4.6

---------

Co-authored-by: catalan <noreply>
Co-authored-by: Moritz Firsching <firsching@google.com>
@danielchin
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danielchin commented Feb 24, 2026

The rebase was a bit messier than expected. I'm also not entirely sure why the CLA check is failing either.

Worse case, I can just spin up a new PR from head.

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arxiv erdos-problems Erdős Problems green-problems Problems from https://people.maths.ox.ac.uk/greenbj/papers/open-problems.pdf linter mathoverflow oeis Conjectures from oeis.org wikipedia

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Erdős Problem 254