ABSTRACT
The concept of a vector is introduced to help social scientists to analyse systems and to provide a compact notation. Bold lower-case letters such as a and a' will be used to denote vectors, to distinguish them from ordinary variables or scalars. Thus a scalar is a single variable or a number and will be denoted as hitherto by italic type; a vector is an ordered array and will be denoted by bold type. Remember that lower-case bold letters without a prime are used for column vectors, and such letters with a prime for row vectors. In arithmetic and in elementary algebra, there are well-known rules for the common operations of addition, subtraction, etc. As already indicated, one purpose in introducing the concept of a vector is to assist in the handling of large systems of simultaneous (linear) equations.
