A separation of determinism, Las Vegas and nondeterminism for picture recognition

The investigation of the computational power of randomized computations is one of the central tasks of current complexity and algorithm theory. In this paper for the first time a "strong" separation between the power of determinism, Las Vegas randomization, and nondeterminism for a computing model is proved. The computing models considered here are finite automata with two-dimensional input tapes (i.e., finite automata recognizing picture languages).