Timeline for R. Smullyan's "Lady or the tiger", Ch. 5, Island of Questioners, problems 11-12
Current License: CC BY-SA 4.0
4 events
| when toggle format | what | by | license | comment | |
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| Dec 27, 2022 at 12:36 | comment | added | Peter LeFanu Lumsdaine | Here’s a comparison I found helpful for intuitively understanding this solution: Suppose we have two asylum patients, Sam and Isaac, who are sane and insane respectively. Then the question “Does Sam believe I am of type B?” is equivalent to “Am I of type B?”, and so as noted in OP’s quoted text, no islander can ask it; whereas “Does Isaac believe I am of type B?” is equivalent to “Am I not of type B?”, so any islander can ask it. So if an islander can ask Arnold “Do you believe I’m of type B?”, then Arnold must be insane like Isaac, and in that case any islander can ask this. | |
| Dec 27, 2022 at 10:55 | comment | added | Ash Shevlyakov | This makes sense, thank you | |
| Dec 27, 2022 at 10:54 | vote | accept | Ash Shevlyakov | ||
| Dec 27, 2022 at 10:38 | history | answered | Carlo Beenakker | CC BY-SA 4.0 |