“…Let f be a continuous self-map of S n × S m with n = m. It is known that the induced linear maps are f * 0 = (1), f * n = (a), f * m = (b) with a, b ∈ Z, f * n+m = (D), where D ∈ Z is the degree of the map f and f * i = (0) for i ∈ {0, ..., n + m}, i = 0, n, m, n + m (see for more details [2]). …”