@inproceedings{ijcai2003p144,
  title     = {SMDP Homomorphisms: An Algebraic Approach to Abstraction in Semi-Markov Decision Processes},
  author    = {Ravindran, Balaraman and Barto, Andrew G.},
  booktitle = {Proceedings of the Eighteenth International Joint Conference on
               Artificial Intelligence, {IJCAI-03}},
  publisher = {International Joint Conferences on Artificial Intelligence},
  editor    = {Georg Gottlob},
  pages     = {1011--1017},
  year      = {2003},
  url       = {https://ijcai.org/proceedings/2003/144},
}