Childline show, suggested to the BBC that they create "Childwatch", a programme about child abuse that was screened on 30 October 1986 on BBC1, the aim being to try to detect children at risk before their lives were in danger. Viewers were asked if they would take part in the survey in an edition of "That's Life!". A helpline was opened after the programme so that any child currently suffering abuse could call for help. Rantzen, together with her BBC producers Sarah Caplin and Ritchie Cogan, therefore suggested they should create a helpline specifically for children in danger or distress, to
Well-founded relation R x". As an example, consider the well-founded relation (N, "S"), where N is the set of all natural numbers, and "S" is the graph of the successor function "x" → "x" + 1. Then induction on "S" is the usual mathematical induction, and recursion on "S" gives primitive recursion. If we consider the order relation (N, <), we obtain complete induction, and course-of-values recursion. The statement that (N, <) is well-founded is also known as the well-ordering principle. There are other interesting special cases of well-founded induction. When the well-founded relation is the usual ordering on the class of