Primitive recursive function: Difference between revisions

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== Elimination of parameters ==
{{expert needed|computer science|section|reason=properly explain the purpose of removing parameters (the text only explains *how* it is used, not *what for* - I guess in some Gödelian (un)computability proof)|date=November 2021}}
 
The original primitive recursion schema was parameter-free. The primitive recursion schema as given may be replaced by one which makes use of fewer parameters. Let <math>w</math> be an elementary pairing function, and <math>\pi_1,\pi_2</math> be its projection functions for inversion.
 
Theorem: Any function constructible via the clauses of primitive recursion using the standard primitive recursion schema is constructible when the schema is replaced with the following.