Given the inductive definition of full binary trees $($FBTs$),$ define i$($T $),$ the number of

internal vertices in tree T $,$ and $($T $),$ the number of leaves in tree T $,$ inductively. The internal

vertices of a tree are all the vertices that are not leaves. Then, use structural induction to

prove that for all FBTs T $,$ i$($T $)=($T $)1.$