A regular grammar has NO stack.
Thus it cannot "remember" a value.
if a language demands to remember at least one value it cannot be regular.
- (B) To check the condition l <m < n, we need to store/remember l and m. hence it cannot be regular.
- (C)To check n<2m we need to store l. It cannot be regular
- (D)To check l=m or m=n we need to store l, m ,n . hence it cannot be regular.
(A) For any value l,m,n>0 by default lmn>0, we need not to check that.
No need to store anything.
It is regular. L= a+b+c+
