first-order class

Summary

first-order class is a second-order class^[1]. It draws 1 Wikipedia views per month (second_order_class category, ranking #42 of 44).^[2]

Key Facts

• first-order class's instance of is recorded as second-order class^[3].
• first-order class's subclass of is recorded as fixed-order class^[4].
• first-order class's subclass of is recorded as class^[5].
• first-order class's Wikidata usage instructions is recorded as A first-order class in Wikidata, e.g., watercraft (Q1229765), bridge (Q12280), or human (Q5), is a class none of whose instances can be classes. Classes that are a subclass of (P279) a first-order class are implicitly a first-order class, e.g., submarine (Q2811) is implicitly a first order class because it is a subclass of (P279) of (a subclass of) watercraft (Q1229765). There are many classes in Wikidata whose instances cannot be classes. It is only necessary to state that such a class is an instance of (P31) first-order class (Q104086571) to emphasize this point, particularly to distinguish it from a related second-order class, such as to distinguish between watercraft (Q1229765) and watercraft type (Q16335899). Before stating that a class is an instance of (P31) first-order class (Q104086571), double check that it cannot have any instances that are classes.^[6].
• first-order class's maintained by WikiProject is recorded as WikiProject Ontology^[7].

Why It Matters

first-order class draws 1 Wikipedia views per month (second_order_class category, ranking #42 of 44).^[2]