Which of the following are rules that ensure a correct recursive function?

a) Each stopping case must perform a correct action (or return the correct value for stopping case) for the condition that invokes it.
b) The recursion must make no more than 1000 recursive calls.
c) The chain of recursive calls eventually must reach one of the stopping cases.
d) The size of the problem solved by the successive recursions must each be larger than the last.
e) For cases that involve recursion: If each recursive calls correctly solve the subproblem (or return the correct value for the subproblem) it solve, then the final

a) Each stopping case must perform a correct action (or return the correct value for stopping case) for the condition that invokes it. , c) The chain of recursive calls eventually must reach one of the stopping cases. , and e) For cases that involve recursion: If each recursive calls correctly solve the subproblem (or return the correct value for the subproblem) it solve, then the final

Mathematical induction may be used to prove that these rules guarantee correctness. We refer the reader to the text, page 567.