 The primitive part of is the quotient of by its content; it is a polynomial with coefficients in , which is unique up to the multiplication by a unit.If the content is changed by multiplication by a unit , then the primitive part must be changed by dividing it by the same unit, in order to keep the equality
which is called the primitive-part-content factorization of .The main properties of the content and the primitive part are results of Gauss's lemma, which asserts that the product of two primitive polynomials is primitive, where a polynomial is primitive if 1 is the greatest common divisor of its coefficients.