Consider the following (Haskell) code:
fib=0:1:zipWith (+) fib (tail fib)
A coworker is trying to assert that this is not a recursive function because fib is simply a list that defines itself with itself and that is somehow different than a function that does the same. I think he's smoking crack.
What do you think?
The example you've given is recursive. But the Fibonacci sequence by nature doesn't have to be. There are iterative versions of the algorithm, and even explicit functions.
Aside from the Haskell implementation here, the Fibonacci Numbers are a sequence defined by a recurrence relation. Mathematically speaking, each term is defined as a function of the preceding terms. Defeat him with mathematical semantics.