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Seven Puzzles You Think You Must Not Have Heard Correctly (2006) [pdf]

math.dartmouth.edu

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Re: Seven Puzzles You Think You Must Not Have Heard Correctly (2006) [pdf]

#5
Love in Kleptopia needs to be explained better. The problem can only be solved if you can afix two padlocks onto a box, and I was presuming the lock box had a single, normally shaped padlock eye, which would make such a thing impossible.

I find this happens a lot with "thought" problems: I can't solve it (and can often prove that) because the rules of the problem are inadequately explained.

Re: Seven Puzzles You Think You Must Not Have Heard Correctly (2006) [pdf]

#6
post #3

Awesome post! I kind of want to find more of these types of things (solutions to seemingly complex questions). If anyone has recommendations would love to hear

I was linked to this blog from a post here the other day. It has a lot of these kinds of questions and the solutions. Here is the prisoners problem:

http://datagenetics.com/blog/december12014/index.html

And here is the dots problem:

http://datagenetics.com/blog/october22012/index.html

Re: Seven Puzzles You Think You Must Not Have Heard Correctly (2006) [pdf]

#7

Love in Kleptopia needs to be explained better. The problem can only be solved if you can afix two padlocks onto a box, and I was presuming the lock box had a single, normally shaped padlock eye, which would make such a thing impossible. I find this happens a lot with "thought" problems: I can't solve it (and can often prove that) because the rules of the problem are inadequately explained.

To get super pedantic, even if that was the case you could use a lock out tag out type device to still attach two locks.

https://www.media-partners.com/upload/i20121017160441/img1.j...

Re: Seven Puzzles You Think You Must Not Have Heard Correctly (2006) [pdf]

#8
I loved this. Some comments. Not really spoilers I hope...

For "Unwanted Expansion" the answer is technically correct but I am displeased that it doesn't prove there wont be any infinite loops. Whereas analyzing invariant in the tree should prove that.

For Boxes in Boxes it says "But, if we take ε to be huge", but how big is huge, and what if it isn't huge? Seems like something in the proof is being hand waved over.

The natives and suicides I enjoyed they really made me go aah!. The irony about the suicides is that the if the people were too dumb to apply the logic, they'd survive.

Re: Seven Puzzles You Think You Must Not Have Heard Correctly (2006) [pdf]

#9

I loved this. Some comments. Not really spoilers I hope... For "Unwanted Expansion" the answer is technically correct but I am displeased that it doesn't prove there wont be any infinite loops. Whereas analyzing invariant in the tree should prove that. For Boxes in Boxes it says "But, if we take ε to be huge", but how big is huge, and what if it isn't huge? Seems like something in the proof is being hand waved over.…

"If we take ε to be huge" just means "let's analyze the growth rate as ε goes to infinity". More formally, what's going on is that you have a function which is polynomial in ε and which is always positive; therefore the leading coefficient must be positive, as if it were negative, the polynomial would be eventually negative.

The question "what if it isn't huge" makes no sense; we can pick ε, it's not some external given. (Actually, as mentioned, we're not picking it to be one specific value but rather letting it tend to infinity, but that's another matter.)

Re: Seven Puzzles You Think You Must Not Have Heard Correctly (2006) [pdf]

#10

Problem 7 has an even more fiendish counterpart: https://en.wikipedia.org/wiki/The_Hardest_Logic_Puzzle_Ever .

To make it more fiendish, what if the gods / natives don't know about each other's TRUE/FALSE/RANDOM status (but they are excellent logicians, so they can intuit any information from answers to your previous questions).
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