# All questions with tag [math: ackermann-function]

2

## Ackermann function

I have problem with an inquiry i require to make use of the function of Ackermann, I require to show that Ack (2,3) = 9. A(2,3)
A(1,A(2,2))
A(1,A(1,A(2,1)))
A(1,A(1,A(1,A(2,0))))
A(1,A(1,A(1,A(1,1)))))
A(1,A(1,A(1,A(0,A(1,0))))))
A(1,A(1,A(1,A(0,A(0,1))))))
A(1,A(1,A(1,A(0,2))))
A(1,A(1,A(1,3)))
A(1,A(1,A(0,A(1,2)))
A(1,A(1,A(0,A(0,A(1,1)))))
A(...

2022-07-04 17:56:36

3

## Ackermann Function primitive recursive

I am reading the wikipedia page on ackermann's function, http://en.wikipedia.org/wiki/Ackermann_function
And I am having trouble understanding WHY ackermann's function is an example of a function which is not primitive recursive.
I understand that the ackermann function terminates, and thus is a total function. So why is it not primitive recursi...

2022-07-03 02:13:30