Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.
Updated
Claim. Let , the golden
ratio. For every there is such that every integer
is for some finite
. Hence the catalog statement erdos_354.parts.ii of
formal-conjectures,
∃ γ ∈ Set.Ioo (1 : ℝ) 2, ∀ᵉ (α > 0) (β > 0),
Irrational (α / β) → IsAddCompleteNatSeq' (FloorMultiples.interleave α β γ)holds with answer(True): the -sequence alone represents every large
integer, its representation maps to the even positions of the interleaving,
and the hypothesis that is irrational is discarded. The result
page
erdos_354_part_ii_solved
and the source card
kitamura_2026_lean_proof_erdos_problem_354_ii
record the theorem and the repository.
Covers. The second question of Problem 354, "What if is replaced by some ?", under the reading "for some ", which is the catalog's existential form; it says nothing under the reading "for every ", which Geneson's claim page answers no, and nothing about base . The author's README says the result does not solve the first question and is stronger than the catalog's part (ii) because the second sequence and the irrational ratio are not needed at this base.
Argument. The even indices give with , , and infinitely often, since otherwise the fractional parts would satisfy the exact Fibonacci recurrence from some point on, whose bounded nonnegative solutions vanish, making two consecutive integers and rational; disjoint carry-one triples represent an interval of consecutive integers by choosing in each triple either or ; the odd indices, , are eventually positive with each term at most twice its predecessor, and adding them one at a time extends the represented interval without gaps past every threshold.
Claimant and postings. Kenta Kitamura (GitHub KitaKen1), who gives
that name in the erdosproblems.com thread comment of 5 September 2026 announcing
the proof, published the repository the same day (the pinned revision) and
opened formal-conjectures PR #5286 to mark part (ii) solved. The README
states that the formalization was developed with assistance from ChatGPT and
OpenAI Codex, using GPT-6 (Astra), the author's own disclosure. The README
reports kernel checks under Lean 4.33.1 against a pinned formal-conjectures
commit and under Lean 4.34.0-rc2 with Mathlib alone, no sorry, admit,
custom axiom, native_decide or unsafe, and #print axioms giving
propext, Classical.choice and Quot.sound; this corpus has built none of
it.
Standing. Claimed, with no acceptance evidence: PR #5286 was approved by
a catalog contributor (GitHub Deicyde) on 2026-09-18 and was still open and
unmerged on 2026-10-07 (labels awaiting-author and solution found). A
catalog pull-request approval checks that a formal statement and its proof
replay in the catalog's build; it is not a named reviewer's examination of the
argument, so it is not reviewed evidence, and formalized evidence needs
this corpus's own build and audit of the file. The catalog's own audit issue
#6542 of 2026-09-24 argues that parts.ii
quantifies existentially and so is provable at one base rather than
asking the variable-base question; the site's commentary does not mention the
proof, and no review or refereed source exists. The reading of the second
question is unfixed by the site and by both of Graham's and Erdős–Graham's
wordings, so this claim settles the question only under one of its two
readings. The thread's own comment raises the concern that the result may
already follow from Hegyvári's 1989 paper, which nobody in the thread
verified.
Depends on. Nothing in this wiki.