“…Our main results are applicable to some cases to which the results in [3,Section 7] are not applicable. [3, (7.3) in Theorem 7.3] corresponds to m−1 i=0 max x∈X Df i (x) < m −m , and, [3, (7.6) [10] and [11], the author considered some regularities of G if X = [0, 1], m = 2, and, f i s are certain linear fractional transformations on X. max Df 0 max Df 1 ≥ 1/4 ≥ min Df 0 min Df 1 can occur. By [14], the inverse function of Minkowski's question-mark function is the solution of (1.1) for the case that X = [0, 1], m = 2, f 0 (x) := x/(x+1) and f 1 (x) := 1/(2−x).…”