... corresponds one and only onepoint on the line and conversely, i.e., there is a one-to-one (see Fig. 1-1) correspondence between the set of real numbers and the set of points on the line. Because of ... both) is often called the union of A and B,denoted by A [ B or A þ B.The set consisting of all elements which are contained in both A and B is called the intersection of A and B,denoted by A \ ... following cases (1) a ¼ b, and (2) either or both of a and b zero.For both a and b positive and a 6¼ b,the proof is by contradiction.Assume to the contrary of the supposition that12ða þ bÞ <ffiffiffiffiffiabpthen14ða2þ...