Consider an alphabet {a, b} as before, write a context-free grammar to generate:

ambn (m 2, n 0, m = n)

That is, each string consists of 2 or more as, followed by any number of bs, provided that the number of as and bs are not equal. Examples are:

aa, aaa, aaaa, . . . , aab, aabbb, aabbbb, . . . , aaab, aaabb, aaabbbb, . . . Again, write the grammar in BNF/EBNF, and show that it generates all and only correct strings.