The concept of k-compatibility measures how many phylogenetic trees it
would take to display all splits in a given set. A set of trees that display
every single possible split is termed a \textit{universal tree set}. In this
note, we find A(n), the minimal size of a universal tree set for n taxa. By
normalising the k-compatibility using A(n), one can then compare
incompatibility of split systems across different taxa sizes. We demonstrate
this application by comparing two SplitsTree networks of different sizes
derived from archaeal genomes.Comment: 9 pages, 2 figure