[techtalk] This talk of N-ary trees and other things...

Mary Gardiner mary at puzzling.org
Sun Mar 25 09:03:12 EST 2001

On Fri, Mar 23, 2001 at 04:55:09PM -0800, Nancy Corbett wrote:
> Knights and Knaves problem. 
> Suppose you visit a strange island with three types of people. Knights,
> who always tell the truth, Knaves, who always lie and Normals who
> sometimes lie and sometimes tell the truth. It is also the custom that
> normals marry only normals, and knights marry only knaves. 
> You meet two couples, Mr. and Mrs. Smith and Mr. and Mrs. Brown. They tell
> you the following: 
> Mr. Brown: Mr. Smith is a knight. 
> Mrs. Brown: My husband is right, Mr. Smith is  a knight. 
> Mrs. Smith: That?s true, my husband is indeed a knight. 
> Can you determine which type each person must be? Explain.

Further to my previous response, I was wondering about solving this in
Prolog (people may have noticed that my propositions were very

I've only been looking at Prolog for a few days though and got very
frustrated at the step of defining Y true, from knight says Y.


Mary Gardiner
<mary at puzzling.org>
GPG Key ID: 77625870

More information about the Techtalk mailing list