“…is a smooth section of T 𝑀 , but may not be a vector field on 𝑀 , because T𝑀 Ď T 𝑀 and T𝑀 -T 𝑀 in general. In order to solve this problem, Odzijewicz and Ratiu [253] proposed (see also further discussion and results in [254,27,28,255,351,287,252]) to define a real Banach Poisson manifold as a pair p𝑀, t¨, ¨uq of a real Banach smooth manifold 𝑀 and a Poisson structure t¨, ¨u on it such that the function 6 : T 𝑀 Ñ T 𝑀 defined above satisfies 6pT 𝑀 q Ď T𝑀 . If p𝑀, t¨, ¨uq is a real Banach Poisson manifold, then every 𝑘 P C 8 F p𝑀 ; Rq determines a unique vector field X 𝑘 P T𝑀 defined by (38), and called a hamiltonian vector field.…”