Polynomial-time globally compatible strengthening of the weak CTF predicate

Determine whether the weak predicate \(\mathrm{satisfies\_ctf}\) can be strengthened to enforce global compatibility between overlapping windows while retaining polynomial-time decidability for sliding-window CNF formulas.

Background

The weak predicate satisfies_ctf\mathrm{satisfies\_ctf} checks each 3-bit window independently and therefore can accept assignments whose adjacent windows disagree on their overlapping variables. The paper gives a formal counterexample demonstrating that weak predicate satisfaction does not imply the existence of a globally compatible path.

For the verified sliding-window fragment, the strong predicate supplies the needed compatibility condition, but the authors leave open whether such a strengthening can be achieved while preserving polynomial-time decidability in the relevant setting.

References

The open question is whether the weak predicate $\mathrm{satisfies_ctf}$ can be strengthened to enforce global compatibility without losing polynomial-time decidability.

Formal Verification of Romanov's Triplet Logic: A Verified Filter for Sliding-window 3-CNF with Application to Structured Formulas  (2608.18445 - Alexandrov, 19 Aug 2026) in Section 5, subsection “Limitations and Future Work,” item 3