1. The problem appears to involve the expression $\frac{a}{b}$ followed by multiple mapping arrows $\mapsto\mapsto\mapsto$. 2. Typically, $\frac{a}{b}$ represents a fraction or ratio of two variables $a$ and $b$. 3. The mapping arrows $\mapsto$ usually indicate a transformation or function mapping from one expression to another. 4. However, since no specific transformation or function is provided after the arrows, the problem is incomplete and cannot be solved as is. 5. Please provide the full expression or the function that $\frac{a}{b}$ is mapped to for further assistance.