S-matrix derivation of the Weinberg Model

By applying only the requirement of asymptotic softness (i.e., the requirement that amplitudes should not grow, asymptotically, faster than that in a renormalizable theory) to various Born amplitudes with four external lines and making some specific assumptions about the number of added particles to meet the requirement, we obtain all of the interaction Lagrangian and relations among the masses and coupling constants of the Weinberg Model.