“…Let , ∈ K 0 and 1 ≤ < ∞. Then U 0 ( ) ∪ U 0 ( ) ⊆ U 0 ( + ).Let + : R × R → R denote the binary operation which was introduced in[10]: , ) (max{| |, | |} − min{| |, | |} ) sgn 2 : R × R → R is given by sgn = sgn( ) if > 0, sgn( ) if ≤ 0 and | | ≥ | |, sgn( ) if ≤ 0 and | | < | |.Here, sgn denotes the usual sign function. Obviously, this operation satisfies two facts:1.…”