%------------------------------------------------------------------------------
% File     : SET999+1 : TPTP v9.2.1. Released v3.2.0.
% Domain   : Set theory
% Problem  : Functions and their basic properties, theorem 21
% Version  : [Urb06] axioms : Especial.
% English  :

% Refs     : [Byl89] Bylinski (1989), Functions and Their Basic Properties
%          : [Urb06] Urban (2006), Email to G. Sutcliffe
% Source   : [Urb06]
% Names    : funct_1__t21_funct_1 [Urb06]

% Status   : Unknown
% Rating   : 1.00 v3.2.0
% Syntax   : Number of formulae    :   40 (  11 unit)
%            Number of atoms       :  104 (   9 equality)
%            Maximal formula depth :   13 (   4 average)
%            Number of connectives :   80 (  16 ~  ;   1  |;  32  &)
%                                         (   8 <=>;  23 =>;   0 <=)
%                                         (   0 <~>;   0 ~|;   0 ~&)
%            Number of predicates  :    8 (   0 propositional; 1-2 arity)
%            Number of functors    :    8 (   1 constant; 0-2 arity)
%            Number of variables   :   71 (   1 singleton;  60 !;  11 ?)
%            Maximal term depth    :    3 (   1 average)

% Comments : Translated by MPTP 0.2 from the original problem in the Mizar
%            library, www.mizar.org
% Bugfixes : v3.4.0 - Renamed to SEU213+3
%------------------------------------------------------------------------------