In this question, you will show that two problems have essentially the same difficulty. In formulating the 3-SAT instance, you may use k (x1, x2, . . . , xm) as notation for a 3-CNF constraint with O(nk) clauses that specifies that at least k of the variables x1 through xm should be true. (a) Prove that 3-SAT P INDEPENDENT SET. (b) Prove that INDEPENDENT SET P 3-SAT.