E12와 E13은 생산 요소 청산 조건이며 E14는 변환 탄력성 불변 함수의 정의식이고 E15는 수입 극대화 일차 필요 조건을 나타낸다.
E12 and E13 are the conditions for the liquidation of aspects of production, E14 could be the definition of the change elasticity invariant function, and E15 is the first-order requirement of income maximization.