A series of index options may be specified using a WITH clause at the end of any CREATE [index-type] INDEX statement:
CREATE [index-type] INDEX index-name
ON table-name (column-name [DESC] [, column-name [DESC]] ...)
[WITH option-name [value] [option-name [value] ...]] ;
Index options control how the index is made, or what sub-type of index is created. Many options are identical to global or server properties set with the SET statement (here), but as options are set directly in the CREATE INDEX statement, they override those server properties, yet only apply to the statement they are set in. Thus, using index options allows modularization of CREATE INDEX statements, making it clearer what settings apply to what index by directly specifying them in the CREATE statement, and avoiding side-effects on later statements.
Note that the WITH clause is only supported in Texis version 7 and later. Previous releases can only set server-wide properties, via the SET statement.