DEFINITION and3_rect()
TYPE =
       ΠP0:Prop
         .ΠP1:Prop
           .ΠP2:Prop
             .ΠP:(Type:46843:cic:/matita/LAMBDA-TYPES/Base-1/types/defs/and3_rect.con)
               .(P0→P1→P2→P)→(and3 P0 P1 P2)→P
BODY =
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