axiom schema

…are therefore usually given by axiom schemata in the sense explained earlier (see above Axiomatization of PC). Given the formation rules and definitions stated in the introductory paragraph of the earlier section on the lower predicate calculus (see above The lower predicate calculus), the following is presented as one standard…

…of axioms is taken by axiom schemata, which, instead of presenting some particular wff as an axiom, lay it down that any wff of a certain form is an axiom. For example, in place of axiom 1 in PM, one might have the axiom schema “Every wff of the form…