For a qualitative analysis of a HQPN, it can be transformed to a flat CPN neglecting all timing aspects and inserting all subnets for their corresponding subnet places. Figure 5 presents the selection of qualitative analysis algorithms implemented in QPN-Tool; it follows mainly version 1.0, [4]. Apart from `classical' algorithms like reachability graph analysis and calculation of P- and T-invariants, novel algorithms for special net classes are offered. Qualitative analysis within QPN-Tool aims at liveness and boundedness. If the HQPN does not exhibit these properties, information from the employed algorithm is extracted in order to indicate the reason for a HQPN being unbounded or not live. All implemented qualitative analysis algorithms are based on Petri net theory and consider the underlying untimed CPN, i.e., timing aspects such as firing delays and frequencies are ignored, and a timed place is replaced by two places and a transition connecting these places.
The same set of Petri net analysis algorithms can be applied to the
HLQPN. In this case every subnet place is replaced by an input and
output place and an additional transition obtained from 
in
the corresponding subnet. For isolated subnets only invariant analysis
can be performed.