- When is a formula said to be in conjunctive normal form (CNF)? Please provide examples. - Any formula that is not in CNF can be transformed into a logically equivalent one that it is in CNF. Please discuss how to perform the transformation. - Provide examples of formulas which are not in CNF and explain how you would transform them into an equivalent CNF formula. - When is a formula said to be in clausal form? Please provide examples of CNF formulas not in clausal form and their corresponding clausal form. - Discuss why the empty clause is unsatisfiable and the empty set of clauses is valid.