Nontrivial approximation for nearly satisfiable ordering CSPs with polylogarithmic error
Determine whether, for any given ordering constraint satisfaction problem (ordering CSP), there exists a polynomial-time algorithm that achieves an approximation value strictly greater than the random-ordering baseline α_random on (1 − ε)-satisfiable instances when ε = 1/polylog(n).
References
Against this background, two basic questions remain wide open:
- Nontrivial Approximation for Nearly Satisfiable CSPs. For a given ordering CSP P (whether or not polynomially tractable), can we obtain a nontrivial approximation for (1 - ε)-satisfiable instances of P, where ε = 1/polylog(n)?
— Approximation algorithms for satisfiable and nearly satisfiable ordering CSPs
(2603.30020 - Makarychev, 31 Mar 2026) in Section 1.1 (Introduction — Ordering CSPs)