Constraints on attribute in group cardinality apply only to non-redundant attributes. A redundant attribute is an attribute with a value that is subsumed by another attribute in the same group.
Cardinality constraints are represented by square brackets containing a minimum value value represented as an integer, optionally followed by two dots and a maximum value represented as an integer or as an asterisk *.
If the maximum is omitted then the maximum cardinality is the same as the minimum cardinality.
If the maximum is an asterisk * the maximum cardinality is unlimited.