The set of all nonnegative real numbers is denoted by R+; the set of all n-tuples of nonnegative real
numbers is denoted by Rn
+ and the set of all n × n matrices with nonnegative real entries is denoted
by Rn×n
+ . We denote the set of all n-tuples of positive real numbers by int(Rn
+). For A ∈ Rn×n
+ and
1 ≤ i, j ≤ n, aij refers to the (i, j)th entry of A. The matrix A = [aij] is nonnegative (positive) if aij ≥ 0
(aij > 0) for 1 ≤ i, j ≤ n. This is denoted by A ∈ Rn×n
+ (A > 0).