Fig. 1. A subnet containing the conjunction coupled implications p₁(p₂p₃) and (p₂p₃)p₄, respectively, represented by the transitions t₁ and t₂.

Fig. 2. A subnet consisting of a p-invariant containing the places p₅ and p₆. The adjacent transitions t₅ and t₆ are connected via read arcs.

Fig. 3. The Petri net modeling the body iron homeostasis. Input and output transitions are depicted as flat rectangles. Logical places are represented by their names and exist in multiple copies in the net which are logically identical; they are shown in grey. The names of the places and transitions are listed in Table 1 and Table 2, respectively.

Fig. 4. Ten clusters of the 85 feasible t-invariants built with 65% accordance within a cluster. (For more details see Table 6.)

The names and IDs of the places of the model (some of these places are equally named, e.g. p7 and p40, but they are identified as different nodes because they were not defined as logical nodes)

The names and IDs of the transitions of the model

The minimal p-invariants of the model

Each of them contains a place carrying already a token in the initial marking of the net.

The transitions listed left hand are connected via read arcs with places not carrying any tokens in the initial marking

Thus, the t-invariants including these transitions and excluding transitions providing tokens at the corresponding places are not feasible. In order to make them feasible they are joint to t-invariants which contain these letter named transitions listed right hand. This processing, according to Eq. (4) leads to feasible t-invariants.

The MCT-sets of the model, built according to Eq. (5) and their contained transitions

The right-hand column names the biological meaning of the MCT-set.

The 85 feasible t-invariants of the model clustered by UPGMA (65%)

The two columns right-hand list the processes contained in the clusters, split into occurring MCT-sets and single transitions. The integers in brackets indicate with which percentage this process is contained in the clusters of invariants. No specification means 100% occurrence of the corresponding transition in the cluster. The column to the left of this gives the total number of invariants in the cluster.