A family ℋ of subgroups of a
finite group G is said to satisfy (property) B∗ if whenever U = H1∩⋯∩ Hr is a
representation of U as intersection of elements of ℋ of minimal length r, then r ≦ 2.
The aim of this paper is to prove THEOREM 1. Let H be a nilpotent Hall
π-subgroup of a group G and assume that if H1,H2∈ Sπ(G) then H1∩ H2⊲ H1.
Then Sπ(G) satisfles B∗.