Yifeng Zeng Prashant Doshi Speeding Up Exact Solutions of Interactive Dynamic Influence Diagrams Using Action Equivalence. 1996-2001 2009 IJCAI http://ijcai.org/papers09/Papers/IJCAI09-329.pdf conf/ijcai/2009 db/conf/ijcai/ijcai2009.html#ZengD09