Past exam of the mathematics course of the University of Cambridge / 2023 / ii / Paper 3 / 4I / d / i / Solution

The grammars are isomorphic. The bijectionmaps every production of $P_0$ to the corresponding production of $P_1$. They are therefore equivalent. Notice that $B$ in the first grammar and $C$ in the second are unreachable; the isomorphism also preserves this irrelevant component.