Editing General recursive function (section)

== Equivalence with other models of computability ==

{{Expand section|date=February 2010}}

In the [[Church's thesis|equivalence of models of computability]], a parallel is drawn between [[Turing machine]]s that do not terminate for certain inputs and an undefined result for that input in the corresponding partial recursive function.
The unbounded search operator is not definable by the rules of primitive recursion as those do not provide a mechanism for "infinite loops" (undefined values).