A graded ideal of a polynomial ring over a field is
componentwise linear if for every nonnegative integer , the ideal
generated by all homogeneous polynomials of degree belonging to
admits a linear resolution. In this paper, we show that the
componentwise linearity of monomial ideals is preserved by the
polarization. As an application, we give a condition to guarantee
that none of the powers of a monomial ideal is componentwise linear.
Key Words: Monomial ideal, linear resolution,
componentwise linear, the gcd condition, polarization.