A new subgroup TG(H)was studied which was defined by Gagola and Isaacsin 2008 for the transfer homomorphism from a finite group G to its subgroup H.It is proved that when H is a nilpotent Hall π-subgroup of G thenTG(H)∩Oπ(G)=[H∩Oπ(G)
H].This result complements a basic diagram in the transfer theory and also offers a more simpler group-theoretic proof for Tate's theorem.