Abstract
It is well known that the Ackermann function can be defined via diagonalization from an iteration hierarchy (of Grzegorczyk type) which is built on a start function like the successor function. In this paper we study for a given start function g iteration hierarchies with a sub-linear modulus h of iteration. In terms of g and h we classify the phase transition for the resulting diagonal function from being primitive recursive to being Ackermannian.
Original language | English |
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Pages (from-to) | 156-162 |
Number of pages | 7 |
Journal | Annals of Pure and Applied Logic |
Volume | 158 |
Issue number | 3 |
DOIs | |
State | Published - Apr 2009 |
Externally published | Yes |
Keywords
- Ackermann function
- Fast growing hierarchy
- Phase transition
- Threshold