ABSTRACT
Very often in mathematics we are interested in combining the elements of some set. We have come across many such examples in earlier chapters of this book. In chapter 1 propositions were combined to form new propositions using logical connectives. The operations of union and intersection of sets introduced in chapter 3 each combine two sets to give a third denoted by A∪B and A∩B respectively. In chapter 5 we looked at composition of functions. Given functions f and g such that the image of f is a subset of the domain of g, we defined the composite function g ◦ f . Other examples are the addition and multiplication of matrices and the familiar arithmetic operations of addition, subtraction, multiplication and division of real numbers.
