ABSTRACT
A scalar is a single number. A vector is a list or array of scalars in one dimension, so to speak; in other words, a series of scalars is arranged one after the other; in a column vector there is only one scalar in each row. A matrix is a rectangular array of numbers arranged in rows and columns. More particularly, a matrix of order m × n is a set of m × n elements arranged in m rows and n columns. Certain special matrices occur fairly frequently in both pure analysis, and in empirical work with arrays of data. It is consequently worth while to pick out these particular matrices, and introduce their names and properties. In defining addition and subtraction of matrices, social scientists took the obvious path, namely that of associating corresponding elements. The definition of matrix multiplication turns out to be much more complicated than that for the operation of multiplying one scalar into another.
