Re: The world's first readable calculus

[Ludwik Kowalski <kowalskiL@MAIL.MONTCLAIR.EDU>]

Can Jack's  problem (see below) be formulated in terms of data to
be presented to a computer program which solves it? I do not
know how to begin solving this program on a computer.
Ludwik Kowalski

> > You are in a land where everyone is either a liar or a truthteller.
> > You desperately need a truthteller for a business deal. You have
> > lunch with 3 people, A, B, and C and ask if any of them is a
> > truthteller.
> >
> > They answer as follows:
> >
> >      A: "There are 3 truthtellers here".
> >       B: "No, only 1 of us is a truthteller."
> >       C: "The second person is telling the truth."
> >
> > Which, if any, are the truthtellers?
> >
> > ANSWER TO THE CHAPTER I PUZZLE
> >
> > All are liars:
> >
> > (a) If A's statement is true, then B's denial is false, and B is a
> > liar. But if B is a liar, then A's statement is false. Therefore A's
> > statement cannot be true and A is a liar.
> >
> > (b) If B's statement is true then either B or C must be the truth
> > teller, since we know that A is not. But if C is the truth teller,
> then
> > B cannot be, making B's statement false. Thus, either B is the only
> > truth teller, or B is a liar.
> >
> > (c) If B is a truth teller, then C's statement is true. But If B is a
> > truth teller, then B must be the ONLY truth teller, so C's
> > statement must be false. Thus C is a liar, and C's statement must
> > be a lie, making B's statement false and C's statement must be a
> > lie, making B's statement false.