• Journal of applied mathematics & informatics
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• v.6 no.1
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• pp.217-226
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• 1999

In this paper we define automata-linearly independence. An automaton M has a basis B iff M is free provided that we assume that the action of S on X $\times$ S is (x,sa) for all a, s $\in$ S and x $\in$ X. if a semigroup S is PRID every subautomaton of a free S-automaton is free.