On Fatou properties of rational languages
نویسندگان
چکیده
We consider so-called Fatou-type properties of rational languages and relations. For example, if the rational expression E(X1; : : : ; Xn) over arbitrary languages X1; : : : ;Xn represents a rational language, then each language Xi can be replaced by a rational language Yi such that E(X1; : : : ;Xn) = E(Y1; : : : ; Yn) holds and moreover Xi Yi for i = 1; : : : ; n. Some similar results for rational relations are established and an open problem on rational relations is stated.
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