Question

A language denoted by a semi-extended regular expression which is regular expression with the additional operation of intersection of regular expressions is
A. regular
B.context-free but not regular
C. context-sensitive but not context-free
D. type 0 but not context sensitive

Answer 1

Answer on Question#38652 – Math - Other

The recognition problem for context-free languages can be reduced to the membership problem for semi-extended regular expressions. So a language denoted by a semi-extended regular expression which is regular expression with the additional operation of intersection of regular expressions is context-free.

Answer: B.