
theorem
  for x,y,z being set holds InnerVertices BitGFA0Str(x,y,z) is Relation
proof
  let x,y,z be set;
  set S1 = GFA0AdderStr(x,y,z);
  set S2 = GFA0CarryStr(x,y,z);
  InnerVertices S1 is Relation & InnerVertices S2 is Relation by Th12,
FACIRC_1:58;
  hence thesis by FACIRC_1:3;
end;
