Sum of squares of irreducible representation dimensions
= Sum of squares of irreducible representation dimensions
{title2=$\sum_\rho(\dim\rho)^2=|G|$}
The regular <group representation> of a finite group over the complex numbers contains each <irreducible representation> with multiplicity equal to its dimension. Consequently the sum of the squared dimensions is the group order. Once a list of distinct irreducibles exhausts this sum, it is complete.