list2 http://www.openmath.org/cd http://www.openmath.org/cd/list2.ocd 2006-03-30 2004-03-30 4 1 experimental Several basic list functions are given in this CD. list_selector application This symbol takes a positive integer n and a list, and represents the n-th element of that list. 2 1 1 first application This symbol represents a function which returns the first elements of its argument, which should be a list. Specification of the first element of the list [1,2,3] 1 2 3 rest application This symbol represents a function which returns a list made up of all the elements except the first of its argument, which should be a list. Specification of the list [1,2,3], apart from the first element 1 2 3 cons application This symbol represents the cons list function. It takes 2 arguments: the second must be a list, where the elements have the same type as the type of the first. The function denotes a new list which has the first argument as its first element followed by the elements of the second argument. cons(first(lst),rest(lst))=lst nil constant The empty list append application The operation of joining one list to another reverse application The reverse of a list size application This symbol is used to denote the number of elements in a list. It is either a non-negative integer. The size of the list (3,6,9) = 3 3 6 9 3 in application This symbol has two arguments, an element and a list. It is used to denote that the element is in the given list.