ABSTRACT
In Maple, it is possible to define new functions, to be used alongside the library functions. They are the user-defined functions. Once a new function is defined, it can be used like any other library function, by substituting any valid expression for its argument. The arrow operator construction can be generalized to the case of functions of several variables. The binary logical operators and and or, and the unary logical operator not, relate expressions whose value is of the logical type. The chapter introduces operations between sets, defined in terms of the notion of membership to a set. The Boolean characteristic function of the set of primes is given by isprime. A function depending on a parameter. The name of the function's argument is invisible from the outside, and in particular, it is unrelated to any variable with the same name that could have been defined.
