An Exponential Gap Between LasVegas and Deterministic Sweeping Finite Automata
A two-way finite automaton is sweeping if its input head can change direction only on the end-markers. For each n ≥ 2, we exhibit a problem that can be solved by a O(n 2)-state sweeping LasVegas automaton, but needs 2Ω(n) states on every sweeping deterministic automaton.
KeywordsTuring Machine Input String Rightmost Column Tree Order Leftmost Column
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