On classes of tractable unrestricted regular expressions
نویسندگان
چکیده
منابع مشابه
On Extended Regular Expressions
In this paper we extend the work of Campeanu, Salomaa and Yu [1] on extended regular expressions featured in the Unix utility egrep and the popular scripting language Perl. We settle the open issue of closure under intersection and provide an improved pumping lemma that will show that a larger class of languages is not recognizable by extended regular expressions. We also investigate some quest...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1985
ISSN: 0304-3975
DOI: 10.1016/0304-3975(85)90021-0