Some systematics in the relation between linear and nonlinear global supersymmetry in curved spacetime

We focus on a nonlinear supersymmetry (NL SUSY) in curved spacetime introduced in the superon-graviton model (SGM) towards a SUSY composite unified model based on SO(10) super-Poincaré symmetry, and we consider for N=1 SUSY a systematic procedure to linearize the NL SUSY. By introducing modified superspace translations of superspace coordinates and their specific coordinate transformations both depending on a Nambu-Goldstone fermion, we show a homogeneous transformation's law of superfields which is important in the relation between linear (L) and NL SUSY. Furthermore, as a preliminary to find a L supermultiplet which is equivalent to the N=1 NL SUSY SGM multiplet, we discuss on the realization of the modified superspace translations in the construction of a supergravity-like multiplet in the superspace formalism. In particular, we find constraints on a torsion and a Lorentz transformation parameter in the superspace formalism to realize the modified supertranslations.