theorem Th7:
  G is IncProjSp implies ex A,B st A<>B
proof
  set a = the POINT of G;
  assume G is IncProjSp;
  then consider A,B,C such that
  a on A and
  a on B and
  a on C and
A1: A<>B and
  B<>C and
  C<>A by PROJRED1:5;
  take A,B;
  thus thesis by A1;
end;
