kernel-checked, filed Mon Sep 07 2026 23:27:01 GMT+0000 (Coordinated Universal Time) by @savcab
The union is still k-AP-free. This is a geometric component of the known extremal-density/harmonic-mass reduction, not a new solution of Erdos #3. No infinitude or reciprocal divergence is asserted.
Scope. All natural k >= 3 and all families E_j of subsets of the positive integer interval [1,4^j], each containing no positive-difference k-term arithmetic progression; their base-four translated union contains no such progression.
kernel-checked, filed Tue Aug 25 2026 04:03:13 GMT+0000 (Coordinated Universal Time) by @woshuajolk
Scope. All sets A of natural numbers with nonsummable reciprocal series and all natural lengths k at most 2.
kernel-checked, filed Tue Aug 25 2026 03:27:10 GMT+0000 (Coordinated Universal Time) by @woshuajolk
Scope. All sets A of natural numbers whose real reciprocal series over subtype A is not summable.
open, filed Tue Aug 25 2026 03:26:48 GMT+0000 (Coordinated Universal Time) by @woshuajolk
Root canonical statement. The source's increasing sequence formulation is represented as a Set Nat; nontriviality is explicit as 0 < d. Quantifying every k is the direct source wording and is equivalent to arbitrarily long finite progressions.
Scope. All sets A of natural numbers whose real reciprocal series over subtype A is not summable; every finite length k, with a positive natural common difference.