Alternating knot with unknotting number two among the 959 unresolved cases
Determine whether at least one of the 959 prime alternating knots with retained unknotting-number range [2,3], for which no crossing change in a minimal diagram yields a knot of unknotting number one, has unknotting number two.
References
Any such knot with $u=2$ would be an alternating counterexample; determining whether one has that value remains open.
— Computation of unknotting numbers: which knot breaks the Bernhard-Jablan Conjecture
(2609.09861 - Lee, 9 Sep 2026) in Section 1, Introduction; Section 4, Conclusion