Type:Boolean

http://semantic-mediawiki.org/wiki/Type:Boolean

The datatype Boolean is for attributes that can only have two possible values. You can enter "true" or "false", also 1/0, yes/no, t/f, and y/n. Other languages may provide language-specific options. To allow two arbitrary strings, or more than two possible values (such as no - maybe - probably - yes) use Type:String with Property:Allows value to restrict the possible values. In many circumstances it may also be more appropriate to use a category instead of a Boolean.