1. CLIQUE NP
To show CLIQUE in NP, we use set V' of vertices as a certificate.
Verifying is polynomial time, check whether for every pair u,v in V',
the edge is in E (
2. L' = 3-CNF-SAT
3. 3-CNF-SAT CLIQUE
Start with instance of 3-CNF-SAT (also called 3CNF).
Let f be 3CNF with k clauses,
For r = 1,2,..,k, each clause has three distinct literals
l1r, l2r, l3r.
Construct a graph G such that f is satisfiable iff G has a clique of size k.
For each Cr in f, put triple of vertices v1r, v2r, v3r in V.
Add edge (vir, vjs) if