Wiki
Wiki

Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.

Updated


Source. Moore, arXiv:2608.09649v1, p. 2, Theorem 2.2 (canonical PDF). The primary input is P. Frankl and V. Rödl, A partition property of simplices in Euclidean space, Journal of the American Mathematical Society 3 (1990), 1–7, Theorem 5.1 on p. 5 and Definition 2.1 on p. 2 (published PDF on Frankl's institutional page, DOI).

Statement. Moore states the theorem as "Every finite affinely independent Euclidean configuration is Ramsey" (p. 2). Explicitly, if SS is such a configuration and r≥1r\ge1 is an integer, there is a dimension NN such that every rr-coloring of RN\mathbb R^N contains a monochromatic congruent copy of SS. The singleton case is included.

Exact external input. Frankl–Rödl prove the stronger statement that an affinely independent set of mm points, identified with a subset of Rm−1\mathbb R^{m-1}, is super-Ramsey. In their definition, for some ϵ>0\epsilon>0 and every sufficiently large nn, a finite set Vn⊆RnV_n\subseteq\mathbb R^n has the property that every subset avoiding the configuration has size less than ∣Vn∣/(1+ϵ)n|V_n|/(1+\epsilon)^n; their definition also gives an exponential upper bound for ∣Vn∣|V_n|. Taking (1+ϵ)n>r(1+\epsilon)^n>r, one color class in VnV_n has size at least ∣Vn∣/r|V_n|/r and therefore contains the configuration. This explains the ordinary Ramsey form used here.

Proof scope. The complete Frankl–Rödl same-paper chain is compiled in Theorem 5.1, and its ordinary-color consequence is recorded separately. The exact external inputs to that earlier proof remain stated there. This page links the consequence used to make the auxiliary simplex Ramsey in Moore's Theorem 1.2.

Bears on. #174.