▁Min ato , ▁the ▁construction ▁of ▁a ▁Z DD ▁for ▁all ▁solutions ▁is ▁too ▁large ▁to ▁solve ▁directly . ▁It ▁is ▁easier ▁to ▁divide ▁and ▁conquer . ▁By ▁div iding ▁the ▁problems ▁into ▁two ▁parts ▁of ▁the ▁board , ▁and ▁construct ing ▁Z DD s ▁in ▁sub spaces , ▁one ▁can ▁solve ▁The ▁Knight ’ s ▁tour ▁problem ▁with ▁each ▁solution ▁containing ▁ 6 4 ▁edges . ▁However , ▁since ▁the ▁graph ▁is ▁not ▁very ▁sparse , ▁the ▁advantage ▁of ▁using ▁Z DD s ▁is ▁not ▁so ▁obvious . ▁ ▁F ault ▁Sim ulation ▁▁ <0x09> N . ▁Tak ah ashi ▁et ▁al ▁suggested ▁a ▁fault ▁simulation ▁method ▁given ▁multiple ▁fault s ▁by ▁using ▁O B DD s . ▁This ▁ded uct ive ▁method ▁transm its ▁the ▁fault ▁sets ▁from ▁primary ▁inputs ▁to ▁primary ▁outputs , ▁and ▁capt ures ▁the ▁fault s ▁at ▁primary ▁outputs . ▁Since ▁this ▁method ▁involves ▁un ate ▁cube ▁set ▁expressions , ▁Z DD s ▁are ▁more ▁efficient . ▁The ▁optim izations ▁from ▁Z DD s ▁in ▁un ate ▁cube ▁set ▁calculations ▁indicate ▁that ▁Z DD s ▁could ▁be ▁useful ▁in ▁developing ▁V L SI ▁C AD ▁systems ▁and ▁in ▁a ▁my ri ad ▁of ▁other ▁applications . ▁ ▁See ▁also ▁▁▁ ▁Order ed ▁Binary ▁Dec ision ▁Di agram ( OB DD ) ▁ ▁Perm ut ation ▁Dec ision ▁Di agram ( π DD ) ▁ ▁Se quence ▁Dec ision ▁Di agram ( Seq DD ) ▁ ▁Sent ential ▁Dec ision ▁Di agram ( SD D ) ▁ ▁Group