 Some of the above-mentioned problems of central planning, regarding inefficiency and concentration of power, have motivated some socialists to explore alternative economic systems in which markets are given a central role. Markets generate problems of their own (especially when they involve monopolies, negative externalities, and asymmetric information). But if regulations are introduced to counter these “market failures”, markets can be the best feasible mechanism for generating matches between demand and supply in large, complex societies (as higher prices signal high demand, with supply rushing to cover it, while lower prices signal low demand, leading supply to concentrate on other products). Market socialism affirms the traditional socialist desideratum of preventing a division of society between a class of capitalists who do not need to work to make a living and a class of laborers having to work for them, but it retains from capitalism the utilization of markets to guide production. There has been a lively debate on this approach, with several specific systems being proposed.