# Ackermann function is not primitive recursive

## Primary tabs

Type of Math Object:
Theorem
Major Section:
Reference
Groups audience:

## Mathematics Subject Classification

Thank you for great entry, CWoo. But I think $A(q,A(2,z))=A(q+4,z)$ at the last of the proof would be a mistake and you should have meant $A(q,A(2,z)).