%--------------------------------------------------------------------------
% File     : LCL123-1 : TPTP v9.0.0. Bugfixed v2.3.0.
% Domain   : Logic Calculi (Right group)
% Problem  : LG-4 depends on LG-2
% Version  : [McC92b] axioms.
% English  : Kalman's axiomatisation of the right group calculus
%            is {LG-1,LG-2,LG-3,LG-4,LG-5}. McCune has shown that LG-2
%            is a single axiom. Other axiomatisations by McCune are
%            {Q-2,Q-3}, {Q-3,Q-4}, S-2, S-3, S-4, P-4, S-6. Show that LG-4
%            depends on LG-2.

% Refs     : [MW92]  McCune & Wos (1992), Experiments in Automated Deductio
%          : [McC92a] McCune (1992), Automated Discovery of New Axiomatisat
%          : [McC92b] McCune (1992), Email to G. Sutcliffe
% Source   : [McC92b]
% Names    : RG-104 [MW92]

% Status   : Unsatisfiable
% Rating   : 0.27 v9.0.0, 0.09 v8.2.0, 0.00 v7.4.0, 0.17 v7.3.0, 0.00 v6.2.0, 0.17 v6.1.0, 0.21 v6.0.0, 0.22 v5.5.0, 0.25 v5.4.0, 0.39 v5.3.0, 0.45 v5.2.0, 0.38 v5.1.0, 0.31 v5.0.0, 0.33 v4.0.1, 0.14 v4.0.0, 0.00 v2.7.0, 0.25 v2.6.0, 0.14 v2.4.0, 0.25 v2.3.0
% Syntax   : Number of clauses     :    3 (   2 unt;   0 nHn;   2 RR)
%            Number of literals    :    5 (   0 equ;   3 neg)
%            Maximal clause size   :    3 (   1 avg)
%            Maximal term depth    :    6 (   2 avg)
%            Number of predicates  :    1 (   1 usr;   0 prp; 1-1 aty)
%            Number of functors    :    6 (   6 usr;   5 con; 0-2 aty)
%            Number of variables   :    6 (   0 sgn)
% SPC      : CNF_UNS_RFO_NEQ_HRN

% Comments :
% Bugfixes : v2.3.0 - Clause prove_lg_4 fixed.
%--------------------------------------------------------------------------
cnf(condensed_detachment,axiom,
    ( ~ is_a_theorem(equivalent(X,Y))
    | ~ is_a_theorem(X)
    | is_a_theorem(Y) ) ).

cnf(lg_2,axiom,
    is_a_theorem(equivalent(X,equivalent(X,equivalent(equivalent(Y,Z),equivalent(equivalent(Y,U),equivalent(Z,U)))))) ).

cnf(prove_lg_4,negated_conjecture,
    ~ is_a_theorem(equivalent(equivalent(equivalent(a,equivalent(b,c)),equivalent(e,equivalent(b,f))),equivalent(a,equivalent(e,equivalent(c,f))))) ).

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