public Transition transitionCollapse(State from, State to) {
		if (currentStep != CONVERT_TRANSITIONS) {
			outOfOrder();
			return null;
		}
		Transition[] ts = automaton.getTransitionsFromStateToState(from, to);
		if (ts.length <= 1) {
			JOptionPane.showMessageDialog(frame,
					"Collapse requires 2 or more transitions!",
					"Too Few Transitions", JOptionPane.ERROR_MESSAGE);
			return null;
		}
		Transition t = FSAToRegularExpressionConverter.combineToSingleTransition(from, to, ts,
				automaton);
		remaining--;
		frame.repaint();
		nextStep();
		return t;
	}