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So the follow up question is to prove that "If the traveler never comes, then no one dies (from the custom)."
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It's already been worked here:
http://forumserver.twoplustwo.com/showfl...rue#Post7711296
I don't know why you find this solution simple, to me it's very complicated. But I also don't understand why you are asking this once you have the solution. If you understand the induction then it becomes obvious that if the traveller doesn't come, the chain thinking event never gets started.