Having a little trouble wrapping my head around trivial functional dependencies and BCNF. Assume you have a relational schema F(A,B,C) with FD's
B,C -> A

Now to see if this is in BCNF, the second FD is a super key but is the first one trivial? Another FD can be made by closure that says B,C - > B, so does this mean that A -> B is trivial as well?