Schaefer's dichotomy theorem states that, for any restriction to Boolean functions that can be used to form these subformulas, the corresponding satisfiability problem is in P or NP-complete. The membership in P of the satisfiability of 2CNF, Horn, and XOR-SAT formulae are special cases of this theorem.
Schaefer's dichotomy theorem states that for any restriction to Boolean functions that can be used to form these subformulas the corresponding satisfiability problem is in P or NP-complete The membership in P of the satisfiability of 2CNF Horn and XOR-SAT formulae are special cases of this theorem