√完了しました! AfB_X Ç p\R 398050
4 1222 (d) Prove that f(f−1(B)) = B for all B ⊆ Y iff f is surjective Proof =⇒ Let y ∈ Y arbitrary We have to show that there exists x ∈ X with f(x) = y Let B = {y} By assumption, f(f−1(B)) = B = {y}, so y ∈ f(f−1(B))By definition this means that there exists x ∈ f−1(B) with f(x) = yTitle show_temppl Author connorja Created Date AMR and f is continuous in a;b Then for each " > 0 there is a piecewise linear function g " such that jf (x) g " (x)j Latin Alphabet For Tundra Nenets Language Writing Alphabet AfB_X Ç p\R"