Table 2.

List of functions used in Algorithm 1

Function	Definition
xMatch	if there is more than one equal abscissa
(abscissa,list)	on the list, returns the pair of
	coordinates corresponding to the
	one which has the minimum ordinate
ordinate	returns the ordinate of a pair of
(abscissa,ordinate)	coordinates
xPrev	returns the pair of coordinates immediately
(abscissa,list)	preceding the abscissa in the list
xNetx	returns the pair of coordinates immediately
(abscissa,list)	after the abscissa in the list
Union(list,list)	joins lists
order(list)	orders a list in increasing order of abscissas
abscissa	returns the abscissas of a pair of
(abcissa,ordinate)	coordinates
trapez(list)	trapezoidal rule for area estimation

Functions are listed in order of appearance.