User blog comment:Alemagno12/Rayo and FOST/@comment-1605058-20160331134819/@comment-25337554-20160331222138

LittlePeng9 is correct. It should be

¬ ∃z(z ∈2 ∧( ¬(z=0)∧ ¬( z =1)) )

,which means that there is no z that z is in the set #2 and neither zero or one.