... thereare examples of rectangles, rhombuses andquadrilaterals which are not squares, D is a propersubset of the other three. In a similar manner wesee that В is a proper subset of A and С is a propersubset ... TorontoCopyright © 1965 by The McGraw-HillCompanies, Inc. All Rights Reserved. Printed inthe United States of America. No part of thispublication may be reproduced, stored in aretrieval system, or ... Theproduct of a set with itself, say Ax A, is denotedby A2. Example 1.12: The reader is familiar with the cartesian plane К2 = К X R as shown below.Here each point P represents an ordered pair...