 We  show that this transition is  induced by an asymmetry between the rate of hiring and the rate of firing of the firms.
<meaning-changed>  We  show that this transition is  induced by an asymmetry between the rate of hiring and the rate of firing of the firms.
 We show that this transition is robust against many modifications of the model, and is generically induced by an asymmetry between the rate of hiring and the rate of firing of the firms.