Although outside of the simple agrarian economy the complexity of technology may increase exponentially , the alternative contractual arrangements are similar. For example, in industry the most important inputs are generally labor and capital instead of labor and land. Nevertheless, the institutional arrangements can be classified first into state or collective-owned firms, on the one hand, and private-owned firms, on the other hand. Then , among the private arrangements, there are several forms: (1) labor hires capital by paying for it at a fixed interest rate, (2) capital hires labor at a fixed wage rate, or (3) both agree to share the output.