Memory size bounds of prefix DAGs

In this report an entropy bound on the memory size is given for a compression method of leaf-labeled trees. The compression converts the tree into a Directed Acyclic Graph (DAG) by merging isomorphic subtrees.Comment: 3 pages, G. R\'etv\'ari, J. Tapolcai, A. K\H{o}r\"osi, A. Majd\'an, Z. Heszberger, "Compressing IP Forwarding Tables: Towards Entropy Bounds and Beyond", In ACM Sigcomm, 201