> A recursive definition is: "natural numbers are 0 or a natural number + 1". Note that this isn't enough by itself to support proof by induction. Consider th

> A recursive definition is: "natural numbers are 0 or a natural number + 1". Note that this isn't enough by itself to support proof by induction. Consider the definition of a list in Haskell which is analogous to the above definition of natural numbers: "lists are [] or a list with an element prepended". Infinite lists satisfy this definition.