When A is an element of R-nxn is an M-matrix we prove the following inequal
ity:
q(A o A(-1)){= 1 for n=2, > 2/n for n > 2,
where A o B is the Hadamard product of two matrices A and B, q(B) = [p(B-1)
](-1) and p(C) denotes the Perron eigenvalue of a nonnegative matrix C. Thi
s also gives a positive answer to the conjecture posed by Fiedler and Markh
am. (C) 2000 Elsevier Science Inc. All rights reserved.