I have expression as $$\sum_{l\in \phi}^{} \sum_{i=1}^{K} \sum_{m\in \phi \setminus l}^{} a(l,i) b(m,i) c(l,m,i)$$ where $m\in \phi \setminus l$ means excluding $l$.
I would like to write this expression without - excluding $l$. Probably I have to separate this into two parts, however, I really did not get it. Can someone please guide me?