THE EXPRESSIVENESS OF LOOPING TERMS IN THE SEMANTIC PROGRAMMING

We consider the language of Delta(0)-formulas with list terms interpreted over hereditarily finite list superstructures. We study the complexity of reasoning in extensions of the language of Delta(0)-formulas with non-standard list terms, which represent bounded list search, bounded iteration, and bounded recursion. We prove a number of results on the complexity of model checking and satisfiability for these formulas. In particular, we show that the set of Delta(0)-formulas with bounded recursive terms true in a given list superstructure HW (M) is non-elementary (it contains the class kExpTime, for all k >= 1). For Delta(0)-formulas with restrictions on the usage of iterative and recursive terms, we show lower complexity.