THEOREMS RELATING TO THE CANONIC ROOTS OF A BINARY
QUANTIC OF AN ODD ORDER.
[From the Philosophical Magazine, vol. xxv. (1863), pp. 206—208.]
I CALL to mind Professor Sylvester’s theory of the canonical form of a binary
quantic of an odd order ; viz., the quantic of the order 2n +1 may be expressed as
a sum of a number n + 1 of (2n +1) th powers, the roots of which, or say the canonic
roots of the quantic, are to constant multipliers près the factors of a certain covariant
derivative of the order (n + 1), called the Canonizant. If, to fix the ideas, we take
a quintic function, then we may write
(a, b, c, d, e, f\x, yj = A (lx + my) 5 + A'(l'x + m'y) 5 + A"(l"x + m"y) 5
(it would be allowable to put the coefficients A each equal to unity ; but there is
a convenience in retaining them, and in considering that a canonic root lx + my is
only given as regards the ratio l : to, the coefficients l, to remaining indeterminate) ;
and then the canonic roots {lx + my), &c. are the factors of the Canonizant
y 3 , -y% yx-, -x â .
a, b , c , d
b, c , d , e
c, d , e , f
It is to be observed that this reduction of the quantic to its canonical form, i.e.
to a sum of a number n-\-1 of (2l)th powers, is a unique one, and that the
quantic cannot be in any other manner a sum of a number n +1 of (2n +1) th poweis.