We consider alternating Turing machines with the bound the number of alternations given by some function. By on restricting the class of machines to those operating in polynomial time we obtain the hierarchy of classes between n≥o ∑pn (the sum of polynomial-time hierarchy of Stockmeyer) and PSPACE. We exhibit some problems to be complete in a special sense in the class of problems solvable by alternating Turing machines performing at most f(n) alternations. Also conditional inequalities between classes are derived. The second part of tpe paper relates these results to the measure STA introduced by Berman [2]. Several properties of that measure are presented. *Please refer to full-text for proper formulas

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Department, Program, or Center

Computer Science (GCCIS)


RIT – Main Campus