Its abstract interface is the class explicit_system_t (which is a descendant of system_t).
It can also compute the enabled transitions in any state of the system using explicit_system_t::get_enabled_trans() method.
The basic functionality of this class is the generation of states of the system using functions explicit_system_t::get_initial_state() and explicit_system_t::get_succs(). The rest of basic functions os contained in the group of methods called "Obligatory part of abstact interface" in the description of explicit_system_t.
System transition is a tuple of process transitions. It can be understood as a product of transitions of processes.
Enabled transition is a system transition + erroneousness of evaluation of guards. It can be untedstood as a product of transition of processes with satisfied guards in a given state. Erroneousness is added because of possible errors during an evaluation of guards (e. g. division by 0).
It depends on the system, which system/enabled transitions are valid.
Example 1: In an asynchronous DVE systems synchonized transitions are represented by system/enabled transitions containing 2 transitions. In the case of the system with property process there is one additional transition in each system/enabled transition.
Example 2: In a case of synchronous DVE systems each system/enabled transition contains exactly process_count transitions.
For generation of enabled transitions in a given state use a method get_enabled_trans().
To create the successors of all enabled transitions stored in a container of enabled transitions (see enabled_trans_container_t) you can use the method get_enabled_trans_succs().
For further informations see explicit_system_t.