• Re: Smullyan's Mockingbird: request for info

    From henhanna@gmail.com@21:1/5 to Marnix Klooster on Mon Jul 4 18:08:33 2022
    On Thursday, September 20, 2001 at 8:52:20 AM UTC-7, Marnix Klooster wrote:
    jdus...@yuma.Princeton.EDU (Jonathan G. Dushoff) wrote in message news:<9nvvmk$nmo$1...@cnn.Princeton.EDU>...
    Marnix Klooster <mklo...@baan.nl> wrote:

    : "Fact 5. Given any male inhabitant X, if Bernardo is a follower of Alfredo
    : and X, then the barber is a follower of X alone."

    Thanks! That means my notes of the problem were correct, and that
    this problem is inconsistent (whether or not you allow X=Y and
    X=Z in the definitions of 'follower'). (See my other post in this
    thread, and http://www.geocities.com/mklooster/calc/tmam-3-7.html,
    for a proof.)

    I haven't found a complete list of the facts, but I am guessing that the intended meaning is "the barber is a follower of X", and that the
    "alone" was added as a misguided attempt at emphasizing the fact that "follower of X" is a _stronger_ condition than "follower of X and Y".
    Does this interpretation make the problem work?
    Hello Jonathan,
    You're completely correct; I hadn't thought of this interpretation.
    (Although looking back at my old notes, I had noticed that the word
    "alone" was superfluous.) I was looking for a deeper meaning in that
    word, which there wasn't. Ah, those formal mathematicians. They even
    try to interpret plain English as logic :-)
    I've updated the page that I mentioned above to reflect the correct interpretation, and the corresponding proof.
    Marnix Klooster
    self emailAddress: 'ln.naab@retsoolkm' reverse

    ths is a lovely thread... in the past, i think i've posted stuff here about things (topics) related to Smullyan

    e.g. about his books, his book covers, his being childhood-friends with R. Feynman.

    a Mockingbird is (Lamda x.xx)... so when you mock a mockingbird, you get a quine.

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