1. We are given the function $Ri(E) = \frac{N(n,a)(E, ti)}{\Phi(E)}$. 2. To understand this expression, note that it represents a ratio of two quantities: the numerator $N(n,a)(E, ti)$ and the denominator $\Phi(E)$. 3. $N(n,a)(E, ti)$ appears to be a function dependent on variables $n$, $a$, $E$, and $ti$. 4. $\Phi(E)$ is a function dependent only on $E$. 5. Without additional information or explicit forms for these functions, we recognize $Ri(E)$ as a function of $E$ defined by the given ratio. 6. If you need to simplify or analyze $Ri(E)$ further, please provide explicit formulas or numerical values for $N(n,a)(E, ti)$ and $\Phi(E)$. 7. For graphing or calculus operations, detailed function forms are necessary. 8. If your goal was only to understand the structure or notation of $Ri(E)$, this concludes the explanation.