“…If a multiplication operation is defined on A such that A is a Banach algebra and L is Leibniz, that is, L(ab) ≤ L(a) b + a L(b) for all a, b ∈ A, then A is a Banach algebra for the norm • 1 . Moreover, if A is a Banach * -algebra with isometric involution and L is a * -seminorm, that is, L(a) = L(a * ) for all a ∈ A, then A is a Banach * -algebra with isometric involution [21,25,37].…”