Learning Two-Tape Automata from Queries and Counterexamples

We investigate the learning problem of two-tape deterministic finite automata(2tape DFAs) from queries and counterexamples. Instead of accepting a subset of 6 3 , a 2-tape DFA over an alphabet 6 accepts a subset of 6 3 26 3 , and therefore, it can specify a binary relation on 6 3 . In [3] Angluin showed that the class of deterministic finite automata (DFAs) is learnable in polynomial time from membership queries and equivalence queries, namely, from a minimally adequate teacher (MAT). In this article we show that the class of 2-tape DFAs is learnable in polynomial time from MAT. More specifically, we show an algorithm that, given any language L accepted by an unknown 2-tape DFA M , learns from MAT a two-tape nondeterministic finite automaton (2-tape NFA) M 0 accepting L in time polynomial in n and `, where n is the size of M and ` is the maximum length of any counterexample provided during the learning process. 1 Introduction In the recent research activity of inductive lear..