  Background. The supertree problem, i.e., the task of finding a common
refinement of a set of rooted trees is an important topic in mathematical
phylogenetics. The special case of a common leaf set $L$ is known to be
solvable in linear time. Existing approaches refine one input tree using
information of the others and then test whether the results are isomorphic.
  Results. A linear-time algorithm, LinCR, for constructing the common
refinement $T$ of $k$ input trees with a common leaf set is proposed that
explicitly computes the parent function of $T$ in a bottom-up approach.
  Conclusion. LinCR is simpler to implement than other asymptotically optimal
algorithms for the problem and outperforms the alternatives in empirical
comparisons.
  Availability. An implementation of LinCR in Python is freely available at
https://github.com/david-schaller/tralda.
