OS (Windows7 Windows7_64 Vista) 
Memory (4GB 2GB 1GB 8GB)
CPU ( Corei7  Corei5 Atom )
Disk (SDD HDD)
Disk2 (SDD HDD)

# groups
{OS Memory Disk}  {Memoery Disk CPU}

# constraints
(if (== [Memory] 8GB) (or (== Vista [OS]) (<> [OS] Windows7)))

(ite (== [Disk] [Disk2]) (== [Memory] 4GB) (<> [Memory] 2GB))

(not (and (<> [OS] Windows7_64) (== 8GB [Memory])))
