
 Formal verification (Site not responding. Last check: 20071029) 
  In the context of hardware and software systems, formal verification is the act of proving or disproving the correctness of a system with respect to a certain formal specification or property, using formal methods. 
  System types that are considered in the literature for formal verification include finite state machines (FSM), labelled transition systems (LTS) and their compositions, Petri nets, timed automata and hybrid automata, cryptographic protocols, combinatorial circuits, digital circuits with internal memory, and abstractions of general software components. 
  The main approaches to implementing formal verification include state space enumeration, symbolic state space enumeration, abstract interpretation, abstraction refinement, processalgebraic methods, and reasoning with the aid of automatic theorem proverss such as HOL or Isabelle. 
 hallencyclopedia.com /Formal_verification (350 words) 
