material | documentation (material ?SUBSTANCE ?OBJECT) means that ?OBJECT is structurally made up in part of ?SUBSTANCE. This relation encompasses the concepts of 'composed of', 'made of', and 'formed of'. For example, a particular instance of plastic is a material of my computer monitor. Note that material is a relation between two instances. If one wants to say that a CorpuscularObject is made up of a subclass of Substance, two assertions are necessary. For example, to say that my computer monitor is made out of the Substance plastic, one would write: (instance ThisPlastic Plastic) and (material ThisPlastic MyComputer). Compare 'component' and 'piece', which are also subrelations of part | |