ck is not expressible as the square root of an octic function of 0.
It will be shown later that all invariants, single or simultaneous, are expressible in terms of symbolic products.
Every covariant is rationally expressible by means of the forms f, u 2, u3,...
It will be ï¿½ shown later that every rational integral symmetric function is similarly expressible.
The discriminant is the resultant of ax and ax and of degree 8 in the coefficients; since it is a rational and integral function of the fundamental invariants it is expressible as a linear function of A 2 and B; it is independent of C, and is therefore unaltered when C vanishes; we may therefore take f in the canonical form 6R 4 f = BS5+5BS4p-4A2p5.