2 problems

Let $t$ be the number of leaves of a tree, and call a tree $t$-minimal if it has $t$ leaves and no other tree with the same number of leaves has a smaller ABC-index, where … for a…

Let $G$ be a tree with minimal atom-bond connectivity (ABC) index among all trees of size $n$. The trees $T_0,T_1,T_2,T_3,T_4,T_5,T_6$ are the structures depicted in Figure. Gutman…