On a formula of J. Deruyts Original Research Article

The formula in the title gives the dimension of the space of all classical semi-invariants of given weight and given degrees, and appears in a memoir of the Belgian mathematician J. Deruyts [2] on classical invariant theory. We interpret this formula in the language of representation theory, and show that it is equivalent to I. Schurʹs [12] formula for an irreducible character of GL(n, C).