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Ackermann function

In computability theory, the Ackermann function, named after Wilhelm Ackermann, is one of the simplest and earliest-discovered examples of a total computable function that is not primitive recursive. All primitive recursive functions are total and computable, but the Ackermann function illustrates that not all total computable functions are primitive…

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Definition

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Table of values

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Inverse

Usage

Advanced semantic analysis

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Map overview Semantic statistics

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Ackermann function

Nodes71
Edges70
Triples126
Avg. degree1.97
Density0.028169
Components1

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Ackermann function

Top relations

related to External links · 58
Ackermann function → Ackermann, Ackermann's, Ackermann's Function, Ady, Algorithms, An, An Easy-Sounding Problem Yields, Archived, August, Ben, BF02187894, Bigger Number, Black, Brubaker, Computational Geometry, Data Structures, Davenport, December, Dictionary, Discrete
related to General remarks · 12
Ackermann function → Ackermann, An, Each, Expressed, For, However, In, It, Its, Knuth's, This, Turing
related to Table of values · 9
Ackermann function → Ackermann, Computing, First, Here, If, Knuth, The, Then, To
related to As a benchmark · 8
Ackermann function → Ackermann's, Brian Wichmann, Dragoș Vaida, Sundblad's, The, The Ackermann, Whetstone, Yngve Sundblad
related to In discrete geometry · 6
Ackermann function → Ackermann, Certain, Davenport, For, Omega, Schinzel
related to Inverse · 6
Ackermann function → Ackermann, Chazelle's, In, Since, Sometimes Ackermann's, This
related to In computational complexity · 5
Ackermann function → Ackermann, For, Petri, The, The Ackermann
related to Computation by TRS, based on hyperoperators · 4
Ackermann function → Ackermann, As Sundblad, Matos, Porto
related to Computation by term rewriting system, based on 2-ary function · 3
Ackermann function → Ackermann, The, TRS
related to Computation by TRS, based on iterated 1-ary function · 2
Ackermann function → Ackermann, The

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Important terminology

function displaystyle ackermann recursive operatorname primitive inverse functions reduction rules time one begin end number sequence stack computation complexity recursion

Entity relationships Subject–Predicate–Object triples

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SubjectPredicateObjectConfidenceSrc
the exponential functioninstance ofincluding very fast-growing functions0.80text
the factorial functioninstance ofincluding very fast-growing functions0.80text
multi-instance ofincluding very fast-growing functions0.80text
superfactorial functionsinstance ofincluding very fast-growing functions0.80text
and even functions defined using Knuth's up-arrow notationinstance ofincluding very fast-growing functions0.80text
a Turing machineinstance ofwhich is obviously computable on a machine with infinite memory0.80text
so is a computable functioninstance ofwhich is obviously computable on a machine with infinite memory0.80text
grows faster than any primitive recursive functioninstance ofwhich is obviously computable on a machine with infinite memory0.80text
is therefore not primitive recursive.Not primitive recursiveThe Ackermann function grows faster than any primitive recursive functioninstance ofwhich is obviously computable on a machine with infinite memory0.80text
therefore is not itself primitive recursive.Proof sketchinstance ofwhich is obviously computable on a machine with infinite memory0.80text
is therefore not primitive recursiveinstance ofwhich is obviously computable on a machine with infinite memory0.80text
Ackermann functionrelated to As a benchmarkThe Ackermann0.60section

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