The following examples illustrate the various forms of synonym rules:
The term d.e.c. or dec produces the alternatives digital- equipment-corp, dec's, or various longer forms. The term dec also produces december: d.e.c. dec dec's : d.e.c dec dec's
digital-equipment-corp
digital-equipment-corporation
digital-equipment-corporation's ;
dec december ;
The terms one or 1 are equal to each other; similarly, for first or 1st: one 1 ;
first 1st ;
The term monkey produces monkey, monkeys, or monkey's. This rule overrides the previous + y... suffix rule, that would produce monkey, monkeies, or monkeie's: monkey monkeys monkey's ;
The terms whereas and wherefore have no alternative forms:
whereas wherefore : ;
Such rules can improve search performance by preventing the generation of alternatives that would otherwise have to be looked up in the index files. If the words are also in a stop file associated with all collections, the rule is redundant.