Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.
Updated
Claim. The statement of [[problems/ramsey_theory/E0547/_index|Problem
547]] as the site prints it, with no range on , is false. For the
tree is and the host is , which has no vertex, so
neither color class of a two-coloring of contains a copy of , and
. Two Lean developments in Boris Alexeev's repository of Lean
proofs, both added on 2026-08-26 and linked above at a pinned commit, prove
this. Erdos547.lean proves Erdos547.not_erdos_547, the negation of the
statement that for every , every tree on Fin n and every simple graph
on Fin (2 * n - 2), is contained in or in its complement; the
proof applies the statement to the one-vertex tree. Erdos547b.lean proves
Erdos547b.not_literalErdos547, the negation of LiteralErdos547, which the
file's docstring calls "the literal, unqualified assertion printed in the
problem database" and which is the same statement, by applying it to the
one-vertex tree and the empty graph on Fin 0; that file's not_erdos_547
restates the result in the first file's form. Neither file names an author, so
the claim is recorded under the repository owner's name. The main theorems of
the two files are large-order bounds recorded elsewhere: Erdos547.erdos_547
on [[problems/ramsey_theory/E0547/claims/2026_08_26_alexeev|the large-order
claim page]], and Erdos547b.eventually_erdos_547, Zhao's theorem, as a
formalization link on
Zhao's claim page.
Depends on. No page of this wiki.
Why it is rejected. It answers the site's wording, not the corrected statement. Problem 547 judges its corrected Statement, the bound for every tree on vertices, which excludes exactly the one-vertex tree; the problem page's Notes give the evidence for that reading. The failure at therefore settles no instance of the corrected Statement. The problem page's Notes credit the result.
Standing. Rejected. The failure needs no source: it is the check written
in the Claim above, and Hua Xu noted it in the site's discussion on 1 May
2026, and the site has not addressed it. No outside reviewer has examined
either file, and this corpus has not built them, so they give formalization
links and no formalized evidence; a build would leave the rejection
unchanged, since the rejection concerns what the theorems answer.