Square-free
From Exampleproblems
In mathematics, an element r of a unique factorization domain R is called square-free, if it is not divisible by a non-trivial square. That is, every s such that 
is a unit of R.
Square-free elements may be also characterized using their prime decomposition. The unique factorization property means that a non-zero non-unit r can be represented as a product of prime elements
Then r is square-free if and only if the primes pi are pairwise non-associated.
Common examples of square-free elements include square-free integers and square-free polynomials.Template:Algebra-stub
