Allowable rule

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A final rule is allowed in respect of a calculus if every formula of the calculus that in the calculus with can be derived using this rule already even without using this rule derived can be.

In this way, proofs of the validity of rules can be carried out: If a rule such as the intersection rule is admissible in a calculus, i.e. can be eliminated, it is valid in the calculus.

literature

  • Peter Schroeder-Heister : admissible / admissibility In: Jürgen Mittelstraß: Encyclopedia Philosophy and Philosophy of Science. Second edition. Volume 8, Metzler 2018, p. 683.
  • Paul Lorenzen : Introduction to Operational Logic and Mathematics. Springer, Berlin a. a., 1955, 2nd edition 1969, further reprints 1994