Proof of `NL = coNL`
groundedproofs/Lax485149Proofs/Bridge.lean · lax-485149
What this proof establishes
Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.
Description
A problem is in NL exactly when its complement is FO(TC) definable, and FO(TC) definability is membership in NL, both by this submission's statements; so the two classes have the same members, and hardness is read off membership.