Hacker Newsnew | past | comments | ask | show | jobs | submitlogin
An Intro to Reverse Induction (ghalib.me)
3 points by gms on April 8, 2009 | hide | past | favorite | 1 comment


Not really reverse induction, but related: The principle of induction is equivalent to the axiom that all non-empty sets of natural numbers have a smallest element. And one can always convert proves from one technique to the other.

As an exercise, try out converting the "Interesting Number Paradox" (http://en.wikipedia.org/wiki/Interesting_number...) to use induction.

("If there were uninteresting numbers, there would be a smallest uninteresting number - but the smallest uninteresting number is itself interesting, producing a contradiction.")




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: