counter-example

[Oscar Ruiz]

I still don't have an answer to my request for  a  counter-example 
to a conjecture of McCluskey and Paull.  Roughly,  the  conjecture 
was  the  following:  A  n-argument  truth  function  is  linearly 
separated if and only if there  exist  no  four  vertices  of  the 
n-cube that form a  parallelogram,  one  pair  of  whose  diagonal 
points are true vertices and the other pair false vertices. It  is 
easy to show that the  condition  is  necessary,  but  E.F.  Moore 
proved in 1957 that it is not sufficient. I  would  like  to  know 
Moore's counter-example, or any other one.

Miguel A. Lerma
Sancho Davila 18
28028 MADRID
SPAIN