Proof of `PTIME = coPTIME` (1st statement)
groundedproofs/Lax535992Proofs/Bridge.lean · lax-535992
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
The Horn fragment is closed under complement, by this submission's statement, and a problem has the finite instances of its double complement; so the two classes have the same members, and hardness is read off membership.