perplexus.info :: Paradoxes : The Exclusive Club

The Exclusive Club (Posted on 2013-07-01)

There is a club called the Exclusive Club. Somebody is a member of this club if and only if he has not shaved anybody who has shaved him. In other words, X is a member of the Exclusive Club if and only if there is no Y such that X shaves Y and Y shaves X.

A barber once claimed that he had shaved every member of the Exclusive Club and nobody else. Show that the barber's claim cannot be true.

No Solution Yet Submitted by Math Man

Rating: 5.0000 (1 votes)

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re(5): solution

| Comment 7 of 8 |

(In reply to re(4): solution by Daniel)

I accept your interpretation , but consider it "weak".

Nothing in the text IMHO precludes the following understanding:

Club members belong to a subset of people not shaving people who did not shave them(PNSPWDNT). This subser we call EXI.CLUB.

There might exist some PNSPWDNT out of this subset.

Using a famous paradox as a basis of logic-oriented puzzle is quite questionable.

Posted by Ady TZIDON on 2013-07-02 05:45:06

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