PPT Slide
In pure Lisp there is no looping; recursion is used instead.
A recursive function is defined in terms of:
1. One or more base cases
2. Invocation of one or more simpler instances of itself.
Note that recursion is directly related to mathematical induction.
An inductive proof has:
1. A basis clause
2. A hypothesis that the theorem is true for some number K
3. An inductive clause that shows it is then true for K+1.