O

Pn(x) = anxn + an−1xn−1 + · · · + a1x + a0 be a polynomial with complex coefficients and an = 0. The number n is the order of the polynomial Pn(x).

order of radical Let A be an ideal of the ring R. The set

√ A = {x ∈ R : xn ∈ A for some n ∈ N}

is called a radical of A. The order of radical of A is the cardinal number of the set

√ A.