Lectures on communication system theory: edited by Elie J. Baghdady. 617 pages, diagrams, 6 × 9 in. New York, McGraw-Hill Book Co., Inc., 1961. Price, $12.50

Abstract

This chapter presents the study of symmetric inseparable double squares of order n, as SIDS(n). A double square can be obtained on superimposing two latin squares and then it a separable square, otherwise it is an inseparable square. Graeco-latin squares, obtained on superimposing two orthogonal latin squares, satisfy conditions, each cell contains two symbols, every symbol occurs exactly twice in each row and in each column and every unordered pair of different symbols occurs exactly twice in the square. If the two latin squares have a common transversal, the graeco-latin square can be changed into a separable double square. A symmetric separable double square can be constructed from a selforthogonal latin square (latin square orthogonal to its transpose).