www.entitylogic.org - entity modelling introduced from first principles
Previously we gave this example model of an atomic nucleus:
This model can be expressed in a different way using the generalisation nucleon of the individual terms proton and neutron by stating: an atomic nucleus is composed of one or more nucleons; every nucleon is either a proton or a neutron. In an entity model diagram the generalisation type is shown as a box containing the specific types; so the model may be expressed thus:
The same generalisation can be used to express that protons and neutrons are combinations of quarks: