Some math conjectures and theorems and proofs can take on a profound, quasi-religious status as examples of the limits of human comprehension. TREE(3) is one of those examples. "You've got all these ...

A new study shows how the present-day distribution of physical traits across species can help explain how the evolutionary process unfolded over time. At this time of year, the words "Yule tree" may ...

A well-founded tree T defined on the vertex set of a graph G is called normal if the endvertices of any edge of G are comparable in T. We study how normal trees can be used to describe the structure ...