Akimasa Morihata, Kiminori Matsuzaki, Zhenjiang Hu, Masato Takeichi. The third homomorphism theorem on trees: downward & upward lead to divide-and-conquer. In Zhong Shao, Benjamin C. Pierce, editors, Proceedings of the 36th ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, POPL 2009, Savannah, GA, USA, January 21-23, 2009. pages 177-185, ACM, 2009. [doi]
Abstract is missing.