Naslund’s polynomial square-difference-free bound over F₃

For polynomial sets over F₃ with no nonzero square differences, determine the largest size at a given degree cutoff. The counterexample target lifts a ten-word code in F₃⁴ to sets of size 810^e below degree 8e and 27·810^e below degree 8e+4.

Why it matters and what counts as progress

Why it matters: It tests Naslund’s proposed bound at q=3,k=2 and improves the growth-exponent lower bound to 16/21.

What counts as progress: Larger square-difference-free polynomial sets or sharper exponent bounds, with exact finite-field and degree restrictions.

How the problem developed

  1. 2023 · Bound and conjecture [1]

    Eric Naslund Constructed square-difference-free subsets of F_q[T] of size q^(3n/4) for odd q and 4 dividing n, and conjectured this bound was tight.

  2. 17 Sept 2026 · Counterexample [2][3]

    J. D. Jones, with Claude, GPT and Grok agents contributing to construction and proof work Disproved the conjectured bound for q=3 at every n divisible by 4 with n ≥ 8; the formalized n=8 construction has 810 elements versus the conjectured 729.

AI contribution

AI-assisted construction refutes a Naslund bound over F₃

A ten-word code in F₃⁴ and an eight-degree lift give square-difference-free polynomial sets of size 810ᵉ below degree 8e and 27·810ᵉ below degree 8e+4. They refute Naslund’s Conjecture 13 at q=3, k=2 for every n divisible by four with n≥8, and imply a growth-exponent lower bound of 16/21.

AI involvementAI-centered
ImportanceNotable
Human understandingFew
Reported

Sources

  1. Naslund’s Conjecture 13
  2. Jones’s Naslund counterexample
  3. AI contribution disclosure
  4. Lean verification record
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