versus is considered as one of the most important open problems in computer science. This consists in knowing the answer of the following question: Is equal to ? It was essentially mentioned in 1955 from a letter written by John Nash to the United States National Security Agency. However, a precise statement of the versus problem was introduced independently by Stephen Cook and Leonid Levin. Since that date, all efforts to find a proof for this problem have failed. To attack the versus question the concept of has been very useful. A well-known problem is . In , it is asked whether a given Boolean formula in is unsatisfiable.
In this paper, we consider the problem of computing the sum of the weighted densities of states of a Boolean formula in . Given a Boolean formula , the density of states counts the number of truth assignments that leave exactly clauses unsatisfied in . The weighted density of states is equal to . The sum of the weighted densities of states of a Boolean formula in with clauses is equal to . We prove that we can calculate the sum of the weighted densities of states in polynomial time.
Diophantine equations of the form are solvable in polynomial time for arbitrary values of . We can apply this Diophantine equation such that is the value of the sum of the weighted densities of states from a Boolean formula in , is the value of each term , where corresponds to the unknown value of . Hence, we only need to check that has all its solutions when such that is always true, where is the number of variables in . Certainly, if the Boolean formula has variables, then has exactly possible truth assignments. In this way, we are able to check whether the Boolean formula is unsatisfiable and obtain a solution for the problem in polynomial time. If any problem is in , then every problem can be decided by a polynomial time algorithm. Consequently, we show the complexity class is equal to .