This paper addresses a number of questions concerning the size of fact
ors of polynomials. Let p be a monic algebraic polynomial of degree n
and suppose q1q2...q(i) is a monic factor of p of degree m. Then we ca
n, in many cases, exactly determine [GRAPHICS] Here parallel-to . para
llel-to is the supremum norm either on [-1, 1] or on {\z\ less-than-or
-equal-to 1}. We do this by showing that, in the interval case, for ea
ch m and n, the n-th Chebyshev polynomial is extremal. This extends wo
rk of Gel'fond, Mahler, Granville, Boyd and others. A number of varian
ts of this problem are also considered.