DEFINITION ex4_ind()
TYPE =
∀A0:Set
.∀P0:A0→Prop
.∀P1:A0→Prop
.∀P2:A0→Prop
.∀P3:A0→Prop
.∀P:Prop
.(∀a:A0.(P0 a)→(P1 a)→(P2 a)→(P3 a)→P)→(ex4 A0 P0 P1 P2 P3)→P
BODY =
Show proof