let x, y, z be set ; :: thesis: InnerVertices (BitGFA3Str x,y,z) is Relation
set S1 = GFA3AdderStr x,y,z;
set S2 = GFA3CarryStr x,y,z;
( InnerVertices (GFA3AdderStr x,y,z) is Relation & InnerVertices (GFA3CarryStr x,y,z) is Relation ) by Th125, FACIRC_1:58;
hence InnerVertices (BitGFA3Str x,y,z) is Relation by FACIRC_1:3; :: thesis: verum