The polynomial hierarchy is an important concept in computational complexity theory. It refers to the set of problems that can be solved in a certain amount of computational time by a polynomial-time algorithm. There are several synonyms for the term polynomial hierarchy that are often used in the field of computer science. One such synonym is the "higher-order polynomial hierarchy," which refers to a more complex set of problems that can be solved in polynomial time. Another synonym is the "recursive polynomial hierarchy," which describes a set of problems that can be solved using a recursive algorithm. Other synonyms include the "exponential hierarchy" and the "bounded arithmetic hierarchy," which describe related but distinct sets of problems.