
theorem Th14:
  for G1 being _Graph, G2, G3 being Subgraph of G1 holds G2 tolerates G3
proof
  let G1 be _Graph, G2, G3 be Subgraph of G1;
  A1: G1 is Supergraph of G2 & G1 is Supergraph of G3 by GLIB_006:57;
  the_Source_of G2 c= the_Source_of G1 & the_Source_of G3 c= the_Source_of G1
    by A1, GLIB_006:64;
  hence the_Source_of G2 tolerates the_Source_of G3 by PARTFUN1:52;
  the_Target_of G2 c= the_Target_of G1 & the_Target_of G3 c= the_Target_of G1
    by A1, GLIB_006:64;
  hence the_Target_of G2 tolerates the_Target_of G3 by PARTFUN1:52;
end;
