Let & > 0. The set {y E R : Ix - yl

Let e > 0. The set {y e R: @ True O False lx yl e) is an open e-neighborhood of x e R. An upper bound m of a set S is the maximum of S if m e S. @ Irue O False Areal number m is an upper bound of a set SC [R if Vs e S, s < m. O True O False If a set iS not finite, then it is denumerable. O True @ False Let and Oc B. Then f -I(D) = O True @ False {x e A : f (x) e D) is the pre-image of D in A. The equivalence class of an element a G A with respect to an equivalence relation R defined on a nonempty set A is the set {b e A : bRa). @ True O False