Chao Wang Gary D. Hachtel Sharp Disjunctive Decomposition for Language Emptiness Checking. 106-122 2002 conf/fmcad/2002 FMCAD http://link.springer.de/link/service/series/0558/bibs/2517/25170106.htm db/conf/fmcad/fmcad2002.html#WangH02