6.3 Fact types 143 b. line segment attribute, which specifies a line segment in two- or three-dimensional space (e.g., road centerline), c. polygon attribute, which specifies a two-dimensional polygon in two- or three-dimensional space (e.g., postal code area). 6.3 FACT TYPES Fact types are occasionally referred to in the literature (and in at least one rule repository tool) as "facts". Fortunately, the SBVR (Object Management Group, 2008) makes a clear distinction between facts and fact types. A fact is either 1. something which is the case or which has occurred, or 2. a true statement. For example, "Canberra is the capital city of Australia" is a true statement (a fact), whereas "Sydney is the capital city of Australia" is a false statement. The artifact "city is the capital city of country" is not a statement as such but can be used as the pro forma for any number of statements, some of which will be true (i.e., facts) and some false, depending on which city and country names you include.