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A '''universal function''' is a function that can, in some defined way, imitate all other functions. This occurs in at least two contexts:
A '''universal function''' is a function that can, in some defined way, imitate all other functions. This occurs in several contexts:
*In [[computer science]], a universal function is a [[computable function]] capable of calculating any other computable function. It is shown to exist by the [[utm theorem]].
*In [[computer science]], a universal function is a [[computable function]] capable of calculating any other computable function. It is shown to exist by the [[utm theorem]].
*In [[cryptography]], a [[One-way_function#Universal_one-way_function|universal one-way function]] is a function that is known to be one-way if one-way functions exist.
*In [[mathematics]], a universal function is one that contains subregions that approximate every [[holomorphic function]] to arbitrary accuracy. The [[Riemann zeta function]] (and some others) have this property, as described in [[Zeta function universality]].
*In [[mathematics]], a universal function is one that contains subregions that approximate every [[holomorphic function]] to arbitrary accuracy. The [[Riemann zeta function]] (and some others) have this property, as described in [[Zeta function universality]].
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Revision as of 13:39, 24 February 2017

A universal function is a function that can, in some defined way, imitate all other functions. This occurs in several contexts: