Further discussion on the existence of optimal solution and the sensitivity analysis for C~2R model

This paper demonstrates the theorems on the existence of optimal solution for C~2R model (D) and extensive C~2R model (D_0) under broader conditions, in which evaluation indexes may take negative value. Then, when output may take negative value, this paper gives a theorem on discriminating DEA efficiency with model (D_0), and on the basis of this theorem presents some theorems on sensitivity analysis as the value of each evaluation index has relative error.