%--------------------------------------------------------------------------
% File     : LCL004-2 : TPTP v9.0.0. Released v2.3.0.
% Domain   : Logic Calculi (Propositional)
% Axioms   : Propositional logic deduction axioms for EQUIVALENT
% Version  : [WR27] axioms.
% English  :

% Refs     : [WR27]  Whitehead & Russell (1927), Principia Mathematica
% Source   : [WR27]
% Names    :

% Status   : Satisfiable
% Syntax   : Number of clauses     :    1 (   1 unt;   0 nHn;   0 RR)
%            Number of literals    :    1 (   1 equ;   0 neg)
%            Maximal clause size   :    1 (   1 avg)
%            Maximal term depth    :    3 (   2 avg)
%            Number of predicates  :    1 (   0 usr;   0 prp; 2-2 aty)
%            Number of functors    :    3 (   3 usr;   0 con; 2-2 aty)
%            Number of variables   :    2 (   0 sgn)
% SPC      : 

% Comments : Requires LCL004-0.ax LCL004-1.ax
%--------------------------------------------------------------------------
cnf(equivalent_defn,axiom,
    equivalent(P,Q) = and(implies(P,Q),implies(Q,P)) ).

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