# [Haskell-cafe] Problem with question 3 about knights and knaves onw ikipedia

Peter Verswyvelen bf3 at telenet.be
Thu Aug 9 17:35:07 EDT 2007

```Indeed, I missed that. This rules out the first answer is "no"

But I still keep the 3 other solutions then :(

>("John is a knight","Bill is a knight","Yes","No ")
>("John is a knave ","Bill is a knight","Yes","Yes")
>("John is a knave ","Bill is a knave ","Yes","No ")

Any more help (or just the solution, I give up) is very welcome to help this
poor man in logic hell ;-)

Oh well, it seems I'm getting too old for this stuff ;)

-----Original Message-----
Sent: Thursday, August 09, 2007 8:22 PM
onw ikipedia

On Thu, 9 Aug 2007 20:07:02 +0200, you wrote:

>("John is a knight","Bill is a knight","Yes","No ")
>("John is a knave ","Bill is a knight","Yes","Yes")
>("John is a knave ","Bill is a knave ","Yes","No ")
>
>Anyone has an idea what I missed here?

You're missing a key element of the problem: After John answers the
first question, the Logician doesn't have enough information to solve
the problem. Think about that for a second, and you will see the light.

Steve Schafer
Fenestra Technologies Corp.
http://www.fenestra.com/
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