The algebraic functional operation of combination is introduced as a programming tool. It has a practical semantic interpretation in building functions which return several results, especially when such functions are directly recursive. Example functions are given whose invocations build multiple results from single recursions, including a new algorithm for batch-probing binary search trees from an unordered list of keys which returns an ordered list of hits.
['Daniel P. Friedman', 'David S. Wise']
Functional combination