%--------------------------------------------------------------------------
% File     : SYN047+1 : TPTP v9.0.0. Released v2.0.0.
% Domain   : Syntactic
% Problem  : Pelletier Problem 17
% Version  : Especial.
% English  : A problem which appears to not be provable by [BBH72].
%            For details of why not, see [Pel82] p.135f.

% Refs     : [BBH72] Bledsoe et al. (1972), Computer Proofs of Limit Theore
%          : [Pel82] Pelletier (1982), Completely Non-clausal, Completely H
%          : [Pel86] Pelletier (1986), Seventy-five Problems for Testing Au
%          : [Hah94] Haehnle (1994), Email to G. Sutcliffe
% Source   : [Hah94]
% Names    : Pelletier 17 [Pel86]

% Status   : Theorem
% Rating   : 0.00 v4.1.0, 0.06 v4.0.1, 0.05 v3.7.0, 0.33 v3.5.0, 0.12 v3.4.0, 0.08 v3.3.0, 0.00 v3.2.0, 0.11 v3.1.0, 0.00 v2.5.0, 0.33 v2.4.0, 0.33 v2.2.1, 0.00 v2.1.0
% Syntax   : Number of formulae    :    1 (   0 unt;   0 def)
%            Number of atoms       :   10 (   0 equ)
%            Maximal formula atoms :   10 (  10 avg)
%            Number of connectives :   12 (   3   ~;   4   |;   2   &)
%                                         (   1 <=>;   2  =>;   0  <=;   0 <~>)
%            Maximal formula depth :    6 (   6 avg)
%            Maximal term depth    :    0 (   0 avg)
%            Number of predicates  :    4 (   4 usr;   4 prp; 0-0 aty)
%            Number of functors    :    0 (   0 usr;   0 con; --- aty)
%            Number of variables   :    0 (   0   !;   0   ?)
% SPC      : FOF_THM_PRP

% Comments :
%--------------------------------------------------------------------------
fof(pel17,conjecture,
    ( ( ( p
        & ( q
         => r ) )
     => s )
  <=> ( ( ~ p
        | q
        | s )
      & ( ~ p
        | ~ r
        | s ) ) ) ).

%--------------------------------------------------------------------------