Definition doubleton_th4_sub1_Out : False := m step1_2.Definition doubleton_th4_sub2_Out : False := n step2_2.Definition doubleton_th4_Out : False := step3 k.

Theorem Doubleton_th4 : forall (X Y Z : Ens) (k : IN Z (Doubleton X Y)) (m : ~ EQ Z X) (n : ~ EQ Z Y), False.