“…We assume that Jf (x * , λ * ) in (3.1) is nonsingular, but we do not assume that λ * I − (m − 1)T (x * ) is nonsingular. When m = 2, the Z-eigenvalue problem here is the same as the H-eigenvalue problem studied in [13] for all m ≥ 2, and it is shown there that λ * I − T (x * ) is always singular and Jf (x * , λ * ) is always nonsingular. For m ≥ 3, however, the difference of these two assumptions is not that big, but the assumption that λ * I − (m − 1)T (x * ) is nonsingular is still the stronger assumption.…”