#L #i elim (drops_F_uni L i) [| * * [ #I #K1 | * #W1 #K1 ] ]
[4: /3 width=3 by ex1_2_intro, or_introl/
|*: #H1L @or_intror * #K2 #W2 #H2L
#L #i elim (drops_F_uni L i) [| * * [ #I #K1 | * #W1 #K1 ] ]
[4: /3 width=3 by ex1_2_intro, or_introl/
|*: #H1L @or_intror * #K2 #W2 #H2L