Of the coefficients of their product.

See Also
--------
polyadd, polysub, polymulx, polydiv, polypow

Examples
--------
>>> from numpy.polynomial import polynomial as P
>>> c1 = (1, 2, 3)
>>> c2 = (3, 2, 1)
>>> P.polymul(c1, c2)
array([  3.,   8.,  14.,   8.,   3.])

)