I am trying to verbally describe how to evaluate a nested group of expressions. What would you call the most-interior group of parentheses as the expression is evaluated?
(((a-b)*(c+d)) - e)
In graph-theory this would be a leaf-node in the tree-representation of the expression. But I'm looking for a term that is not specific to graph-theory. The "next order of operation" comes to mind but that's not quite right, as I'm just looking at the parentheses grouping.
In the case above, I want to identify the most-interior groupings as (a-b) and (c+d). Is there a better way to refer to these other than "most-interior grouping" or leaf nodes of a tree graph?