readme.txt

Ackermann-nonrecursive.cpp, 艾克曼, 非递回

Ackermann function

In recursion theory, the Ackermann function or Ackermann-Peter function is a simple example of a general recursive function that is not primitive recursive. General recursive functions are also known as computable functions. The set of primitive recursive functions is a subset of the set of general recursive functions. Ackermann's function is an example that shows that the former is a strict subset of the latter.

It takes two natural numbers as arguments and yields another natural number, using the notation A(m,n). Its value grows rapidly; even for small inputs, for example A(4,2)[1] and A(4,3), the results are large numbers. These large numbers in the m=4 row can also be expressed using tetrations.

http://en.wikipedia.org/wiki/Ackermann_function