The computability aspects of Kőnig's lemma have been thoroughly investigated. The form of Kőnig's lemma most convenient for this purpose is the one which states that any infinite finitely branching subtree of formula_1 has an infinite path. Here formula_2 denotes the set of natural numbers (thought of as an ordinal number) and formula_1 the tree whose nodes are all finite sequences of natural numbers, where the parent of a node is obtained by removing the last element from a sequence. Each finite sequence can be identified with a partial function from formula_2 to itself, and each infinite path can be identified with a total function. This allows for an analysis using the techniques of computability theory.