Note on Soft Graviton theorem by KLT Relation
  Recently, new soft graviton theorem proposed by Cachazo and Strominger has inspired a lot of works. In this note, we use the KLT-formula to investigate the theorem. We have shown how the soft behavior of color ordered Yang-Mills amplitudes can be combined with KLT relation to give the soft behavior of gravity amplitudes. As a byproduct, we find two nontrivial identities of the KLT momentum kernel must hold. 
Yi-Jian Du, Bo Feng, Chih-Hao Fu, Yihong Wang
hep-th hep-ph