Uses of Ackermann function?
In our discrete mathematics course in my university, the teacher shows his students the Ackermann function and assign the student to develop the function on paper.
Beside being a benchmark for recursion optimisation, does the Ackermann function has any real uses ?
Answer
Yes. The (inverse) Ackermann function appears in complexity analysis of algorithms. When it does, it means you can almost ignore that term since it grows so slowly (a lot like log(log ... log(n)...)) i.e. lg*(n). For example: Minimum Spanning Trees (also here) and Disjoint Set forest construction.