Abstract
Robin's criterion states that the Riemann Hypothesis is true if and only if the inequality $\sigma(n) < e^{\gamma} \times n \times \log \log n$ holds for all natural numbers $n > 5040$, where $\sigma(n)$ is the sum-of-divisors function of $n$ and $\gamma \approx 0.57721$ is the Euler-Mascheroni constant. We also require the properties of {\em superabundant numbers}, that is to say left to right maxima of $n \mapsto \frac{\sigma(n)}{n}.$ In this note, using Robin's inequality on superabundant numbers, we prove that the Riemann Hypothesis is true.