Which of the following grammar rules violate the requirements of an operator grammar? P, Q, R are nonterminals, and r, s, t are terminals.
P $\rightarrow$ Q R
P $\rightarrow$ Q s R
P $\rightarrow \: ε$
P $\rightarrow$ Q t R r
answer is B .because operator grammer does not contain 1) nullable variable 2) 2 adjacent non-terminal on rhs of production
no, PQ-->RsT will also not be in operator grammer, because
PQ is present in LHS means it has also been generated by some production like V ---> αPQβ which is also in grammer and voilating operator precedence condition..