removespecifiedstates

RemoveSpecifiedStates is a function or operation in state-based modeling that produces a new machine by removing a specified set of states from an existing finite state machine (FSM), automaton, or stateful model. The purpose is to simplify the model, deprecate features, or enforce constraints by eliminating certain behaviors represented by those states.

Inputs and outputs: The input consists of an FSM and a collection of states to remove. The output is a new FSM that contains only the remaining states and transitions that do not involve any removed states. Transitions that previously entered or left a removed state are eliminated. The function may also adjust the initial or final states depending on options or defaults.

Behavior with respect to initial and final states: If the initial state is removed, the implementation may select a new initial state from the remaining set or indicate that the machine becomes empty. If any final state is removed, the remaining final states are preserved. In some configurations, removing states can cause the machine to accept fewer strings, reject more, or alter the language recognized by the automaton.

Options and caveats: Many implementations offer options such as pruning inaccessible states, preserving the original language, or raising an error if the initial state is removed. In nondeterministic machines, removing states can introduce nondeterministic effects elsewhere, or require recomputation to understand the resulting language. After removal, a minimization or determinization step may be advisable to restore a compact representation.

Example usage: Given a DFA modeling a workflow, removing states corresponding to deprecated steps may simplify the model while preserving all remaining accepted behaviors. However, language equivalence should be verified if preserving exact language is required.