Full Idea
An axiom system for a logic contains three elements: a set of axioms; a set of inference rules; and definitions for proofs and theorems. There are also definitions for the derivation of conclusions from sets of premises.
Gist of Idea
Axiom systems of logic contain axioms, inference rules, and definitions of proof and theorems
Source
Rod Girle (Modal Logics and Philosophy [2000], 6.5)
Book Reference
Girle,Rod: 'Modal Logics and Philosophy' [Acumen 2000], p.92