Queries are used to investigate the properties of a CPN. It is, e.g., possible to investigate the reachability, boundedness, home, liveness, and fairness properties using standard queries; and non-standard queries can be created by writing CPN ML functions.
The query functions that are available are described in the state space tool manual.
ExcAvlLookup exception will be raised, if you attempt to access a node that is not found in the state space that has been calculated.
For example, if you use the Evaluate ML tool to evaluate the expression
DeadMarking(2) before applying the Calculate state space tool, then the
ExcAvlLookup exception will be raised, since node number 2 cannot exist in a state space that has not yet been calculated.