ents of List not in SubList, also in the order they appear in List. subset/2True if all elements of SubSet belong to Set as well. subtract/3Delete all elements in Delete from Set. sum_list/2Sum is the result of adding all numbers in List. union/3True if Set3 unifies with the union of the lists Set1 and Set2.

F.2.27 library(main)

argv_options/3	Parse command line arguments.
argv_options/4	As argv_options/3 in __guided__ mode, Currently this version allows parsing argument options throwing an exception rather than calling halt/1 by passing an empty list to ParseOptions.
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