Canonizant

In mathematical invariant theory, the canonizant or canonisant is a covariant of forms related to a canonical form for them.
Canonizants of a binary form.
The canonizant of a binary form of degree 2"n" – 1 is a covariant of degree "n" and order "n", given by the catalecticant of the penultimate emanant, which is the determinant of the "n" by "n" Hankel matrix with entries "a""i"+"j""x" + "a""i"+"j"+1"y" for 0 ≤ "i","j" < "n".