Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.
Updated
JenW1N: Lean proof of Problem 354 part (i), Conjectures.io record 815c1d5f
evidence/: Retains the site's solution file Main.lean as fetched on 2026-09-28, the bytes the site's kernel accepted, unedited and not built here.
jenw1n_2026_erdos_354_part_i_lean_proof: Record identity, the site's dates and review decision, its verification report, the task's pinned statement and the public standing of the result as of 2026-09-28.
target: The accepted theorem: the catalog statement of the first question of Problem 354 with its answer instantiated to true, unfolded to the site's wording, with the proof's reduction chain.
JenW1N (the solver handle the bounty site credits), Erdős problem 354 -
part i, Lean 4 proof accepted by the bounty site Conjectures.io, record
815c1d5f-3afb-4430-8e2c-260d9038f5b0
(https://conjectures.io/results/815c1d5f-3afb-4430-8e2c-260d9038f5b0),
attacked as Prove: Lean verification 11 September 2026, review approval 15
September 2026 under the site's manual-review policy v3, certification 16
September 2026, bounty paid. Conjectures.io is a Bittensor subnet that
publishes Erdős problems as Lean statements pinned to a commit of the
formal-conjectures catalog and pays for kernel-checked proofs accepted in
its review.
The folder holds no folder-name PDF: the source is the Lean file the site's
record publishes, with no write-up, so the folder-name Markdown file
source record is the source
itself and records the URLs, the verified statement, the site's dates, its
review decision and verification report, and the public standing of the
result (the library's no-PDF shape). The Lean file is retained unedited
under evidence/assets/solution_815c1d5f/Main.lean; the file's header
declares no author and no AI system.
Provenance of the proof file.
https://conjectures.io/results/815c1d5f-3afb-4430-8e2c-260d9038f5b0/solution/download
(the page .../solution shows the first 500 of its lines), fetched (HTTP 200); 485,414 bytes, 10,152 lines; two other fetches
on the same day (02:41 and 03:49 UTC) returned identical bytes. Header: "A proof
of the full Erdős 354(levelIndex) proposition" (the "(levelIndex)" is a
mechanical rename of an identifier i). The file is 130 sections, each headed
/- Source: <name>.lean -/, from DigitTransport.lean to FullTarget.lean,
all in the namespace Erdos354Formal, with the final theorem target at
line 10148.
Read status: claims checked. The final theorem was read against the site's printed type, the task bundle's metadata and the catalog file, and its reduction chain to two criteria on binary digits was read (result page). The mathematical core (about 9,000 lines: a joining and disjointness argument on the binary digit sequences of and through empirical measures, tower shift spaces and rigidity) was not read line by line, and the file was not built here, so the kernel check is the site's, on a single kernel. No proof was verified here and no kernel credit is claimed.
Bears on. Problem 354: the status-defining source for the first question (base ), answered yes exactly in the site's formulation; the second question (a base ), strong completeness and the set-union reading are untouched.
The verified statement
The record page, the task page and the task bundle's source-metadata.json
print the target type
True ↔ ∀ α > 0, ∀ β > 0, Irrational (α / β) →
IsAddCompleteNatSeq' (Erdos354.FloorMultiples.interleave α β 2)which is Erdos354.erdos_354.parts.i of
FormalConjectures/ErdosProblems/354.lean with answer(sorry) instantiated
to True, at the pinned catalog commits 8432eac9 (record page) and
6a786f99 (task bundle), both with the same source type SHA-256. Neither pinned
commit is reachable on GitHub; the catalog's default branch,
prints the same statement and docstring. In the catalog, FloorMultiples a γ n
is , interleave a b γ n is
FloorMultiples a γ (n / 2) for even and FloorMultiples b γ (n / 2) for
odd , subseqSums' A is the set of sums over finite
index sets , and IsAddCompleteNatSeq' A says every sufficiently large
integer lies in subseqSums' A. So the theorem says: for all
with irrational, every sufficiently large integer is
for
some finite , each index used at most once and equal values
at different indices counted separately, which is the site's "That is" clause
read clause for clause (the result page gives the correspondence).
The proof's own lemmas interleave_even and interleave_odd (lines 268--274)
unfold the catalog's interleave by simp into the two floor sequences; they
compile only against the corrected n / 2 form of the definition (PR #1330, 3
December 2025), so the kernel acceptance itself shows the pinned definition is
the corrected one, which the type hash alone (naming the constant, not its body)
would not.
Acceptance shown on the results page
The record page, shows Lean verification Passed
(verified; the review text dates the acceptance to
20:48:55 UTC that day), Conjectures review Approved (REVIEW_APPROVED
under manual-review policy v3, decided 15 September 2026), Reward Paid and
Certified 16 September 2026; checked in 3 min 3 s in a Landrun-with-seccomp
sandbox by validator-428166381eba73ec1c61148f6d74866b74145563. The
verification report lists a static scan ("no imports, no axiom declarations, no
sorry, no native_decide, no unsafe options"), Challenge built, source type hash
matches, Solution built, "Statement unchanged" ("exactly the same canonical type
as the task's target - it was not weakened or restated"), "Only permitted
axioms" (propext, Quot.sound, Classical.choice), "Lean kernel accepted"
and the second kernel "Not run" ("The verdict rests on a single kernel
implementation"). The review note says the submission "proves the affirmative
answer to Erdős Problem 354(i)", that "The accepted Lean statement preserves the
intended multiset interpretation and includes every exponent", that no
qualifying earlier public solution was found (the part (ii) formalization "uses
a base below 2 and does not prove part (i)"; "Fan's September 2026 completeness
criterion leaves the relevant two-ray case unresolved"; the full proof claim
posted on 13 September, with a repository created 12 September, "is later than
acceptance"), and that these findings "are not a guarantee of absolute novelty".
The accepting body is the bounty site alone: no refereed publication, no
write-up, no erdosproblems.com acceptance and no formal-conjectures catalog
agreement was found on 2026-09-28; the catalog's default branch keeps both parts
research open.
Route of the proof file
The final theorem target : fcTypeOfName% "Erdos354.erdos_354.parts.i"
(line 10148) closes by exact full_target_of_symbolic_digit_criteria
applied to symbolicallyDisjoint_of_boundedZeroRuns (line 8921) and
forwardTransport_of_not_symbolicallyDisjoint (line 10122). Its chain:
full_target_of_normalized(line 346) reduces to :exists_common_scale(line 337) picks with andcomplete_of_dyadic_scale(line 329) pulls completeness back along the injective index shift ;pair_sum_mem_subseqSums(line 276) maps a pair of finite index sets to one index set of the interleaving.full_target_of_dynamical_criteria(line 402) derives the target from a symmetric relation on pairs and three inputs: implies the completeness of the pair for ; bounded zero runs in the binary digits of imply ; and when has unboundedly many ones and fails, ones of are transported forward into ones of at a positive offset.full_target_of_symbolic_digit_criteria(line 1118) instantiates withSymbolicallyDisjoint(line 1084) throughcompletePair_of_symbolicallyDisjoint(line 1102).- The two criteria fill the rest of the file: carry combinatorics and
transport for the bounded-zero-runs case, and, for the transport case, a
joining argument on the shift spaces of the digit sequences through
empirical measures, tower alphabets and an rigidity exclusion
(
cross_marked_rigidity_exclusion). Not read line by line here.
A text scan of the file found 601 theorem or lemma declarations and 91
def lines at column zero, six abbrevs and one inductive
(HasCarryPairCount, line 6928), all inside Erdos354Formal; open
commands naming only Filter, MeasureTheory, Topology,
TopologicalSpace and the scoped ENNReal; no sorry, axiom,
native_decide, unsafe, set_option, implemented_by, extern,
opaque or _root_; no instance, notation, macro, elab or
syntax; no partial definition (the textual hits of partial are
identifiers and comments); decide only as a classical decidability term
(line 919) and on finite Bool lemmas (lines 1142--1164, 1334, 1352); and
no redefinition of FloorMultiples, interleave, subseqSums' or
IsAddCompleteNatSeq'. The site's static scan reports no imports in the
submitted source: the imports and the namespace Bounty wrapper are
supplied by the task's trusted header.
Neighbors
The later manuscript claiming the stronger strong-completeness statement is filed at yu_chen_2026_erdos_problem_354_i_strong_completeness_two_dyadic_floor_sequences (unreviewed; the site's review notes it as later than acceptance). The part (ii) Lean proof the review mentions is kitamura_2026_lean_proof_erdos_problem_354_ii, and Fan's criterion is fan_2026_strongly_complete_sets_conjecture_erdos; the problem's origin is Question 12 of Graham's 1971 survey.