theory-derivation
Definition
A theory-derivation is a tuple \(\left( \boldsymbol{I}, \boldsymbol{\Phi} \right)\)
Where:
\(\boldsymbol{I}\) is a finite collection of inference-rules,
\(\boldsymbol{\Phi}\) is a finite sequence of formulas \(\boldsymbol{\phi_1}, \boldsymbol{\phi_1}, \ldots, \boldsymbol{\phi_n}\) each of which is either an axiom schema, an axiom, a definition, or a propositional formula inferred from previous formula (including theorems of other theories being extended by this derivation) by one of the inference-rule in \(\boldsymbol{I}\).
Bibliography
[MGZ21, p. 20]