• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.551-558
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• 2004

We shall discuss some properties of quasi-homomorphisms associated with automata. We shall give some characterizations in terms of characteristic semigroups for regular and invertible attomata.

• Journal of applied mathematics & informatics
• /
• v.16 no.1_2
• /
• pp.559-569
• /
• 2004

In this paper we shall discuss the quasi-perfect automata associated with power automata. We shall give the fact that its power automaton is invertible if an automaton A is quasi-perfect. Moreover, some subgroups and normal subgroups of the characteristic semigroup X(M) will have the very interesting parts in their structures.