Trees, Hierarchies, and Graphs

Abstract

Our world is filled with nested classifications, both those defined by nature and by man. The universe itself is hierarchical in nature, made up of galaxies, stars, and planets, each classified by the outermost set. One of the more obvious hierarchies here on Earth is probably the food chain that exists in the wild; a lion can certainly eat a zebra, but alas, a zebra will probably never dine on lion flesh. And of course, we’re all familiar with corporate management hierarchies— which some companies try to kill off in favor of matrixes, which are not hierarchical at all⋯ but more on that later!