ternary mekso/mathematical operator: radical; for input (x,y,z), it outputs the largest y-th-power-free product of prime divisors of x in structure (ring) z.
Contextless defaults: z is usually the standard ring of integers (with primes being the standard set of prime numbers; note that this excludes 0, 1, and all negative numbers from the set of primes); y = 2.