Let L be a language in P. Prove it is reducible to any language in NP, including any language in P, which contains at least one string but doesn't contain all the strings For the next three problems, prove that the problem is NP-complete. PROBLEM: 4-SAT INPUT: A set of m clauses in 4-CNF form, n variables. OUTPUT: "Yes" if and only if there is a truth assignment which satisfies all the clauses. Use 3-SAT Let L be a language in P. Prove it is reducible to any language in NP, including any language in P, which contains at least one string but doesn't contain all the strings For the next three problems, prove that the problem is NP-complete. PROBLEM: 4-SAT INPUT: A set of m clauses in 4-CNF form, n variables. OUTPUT: "Yes" if and only if there is a truth assignment which satisfies all the clauses. Use 3-SAT