Past exam of the mathematics course of the University of Cambridge / 2025 / ii / Paper 2 / 4F / b / iv / Solution

This language is context-free. LetThe nonterminal $T$ produces exactly $1^m{0}^m$ with $m>0$. The base production for $S$ supplies one leading and one trailing zero, and each recursive production supplies one more of each. Thus $S$ produces exactly