EN
Let E be a Riesz space. By defining the spaces $L¹_{E}$ and $L_{E}^{∞}$ of E, we prove that the center $Z(L¹_{E})$ of $L¹_{E}$ is $L_{E}^{∞}$ and show that the injectivity of the Arens homomorphism m: Z(E)'' → Z(E˜) is equivalent to the equality $L¹_{E} = Z(E)'$. Finally, we also give some representation of an order continuous Banach lattice E with a weak unit and of the order dual E˜ of E in $L¹_{E}$ which are different from the representations appearing in the literature.