Under reasonable assumptions about the complex structure of the set of singularities on the Coulomb branch of $mathcal N=2$ superconformal field theories, we present a relatively simple and elementary argument showing that the scaling dimension, $Delta$, of a Coulomb branch operator of a rank $r$ theory is allowed to take values in a finite set of rational numbers$Deltain big[frac{n}{m}big|n,minmathbb N, 0<mle n, gcd(n,m)=1, varphi(n)le2rbig]$ where $varphi(n)$ is the Euler totient function. The maximal dimension grows superlinearly with rank as $Delta_text{max} sim r lnln r$. This agrees with the recent result of Caorsi and Cecotti.
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