%------------------------------------------------------------------------------
% File     : GRA118-1 : TPTP v9.3.1. Released v9.3.0.
% Domain   : Graph Theory
% Problem  : Ramsey number r(3,3) = 6 with Peano axioms
% Version  : Especial.
% English  : The Ramsey property that if an undirected graph has at least
%            R(m,n) vertices, then it must have either an m-clique or an
%            n-anticlique.

% Refs     : [Ram30] Ramsey (1930), On a Problem of Formal Logic
%          : [Kal24] Kalizyk (2024), Email to G. Sutcliffe
% Source   : [Kal24]
% Names    : r_3_3_6_p [Kal24]

% Status   : Unsatisfiable
% Rating   : 0.25 v9.3.0
% Syntax   : Number of clauses     :    5 (   1 unt;   2 nHn;   4 RR)
%            Number of literals    :   17 (   9 equ;   6 neg)
%            Maximal clause size   :    6 (   3 avg)
%            Maximal term depth    :    2 (   1 avg)
%            Number of predicates  :    2 (   1 usr;   0 prp; 2-2 aty)
%            Number of functors    :    2 (   2 usr;   1 con; 0-1 aty)
%            Number of variables   :   11 (   1 sgn)
% SPC      : CNF_UNS_RFO_SEQ_NHN

% Comments :
%------------------------------------------------------------------------------
cnf(rsym,axiom,
    ( ~ r(X,Y)
    | r(Y,X) ) ).

cnf(rn3cl,axiom,
    ( X = Y
    | X = Z
    | Y = Z
    | ~ r(X,Y)
    | ~ r(X,Z)
    | ~ r(Y,Z) ) ).

cnf(rn3acl,axiom,
    ( X = Y
    | X = Z
    | Y = Z
    | r(X,Y)
    | r(X,Z)
    | r(Y,Z) ) ).

cnf(pfnc,axiom,
    f(X) != c ).

cnf(pfinj,axiom,
    ( f(X) != f(Y)
    | X = Y ) ).

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