  We generalize the definition of strong positive partial transpose (SPPT) to
the multipartite system. The tripartite case was first considered by X.-Y. Yu
and H. Zhao [ Int. J. Theor. Phys.,54, 292, (2015)]. In this extension,
unfortunately, desired properties such as the PPT of SPPT states the
separability of super and pure SPPT states are not preserved. In contrast, this
paper provides an alternative generalization to multipartite cases with these
properties preserved. We also provide sufficient conditions for the
separability of SPPT states.
