National Wealth and Net National Product
扩展了Solow和Weitzman关于国民净产出与资本价值关系的经典结论，证明在包含不可再生资源和内生知识的情况下，国民净产出等于累积资本价值的利息，并揭示了资本的前向与后向视角的对偶性。
Solow (1986) established that corresponding to constant consumption programs with essential exhaustible resource stocks there was a capital value that was remaining constant. He thus obtained a Hick's type of result, namely that current consumption left capital intact. Solow was using Weitzman (1976) as a point of departure. It turns out that there is a quite general Solow-type of result, namely that NNP(t) is on the value of accumulated capital, V(t), where V(t) can include diminutions in natural resource stocks and the interest rate is the social discount rate. A Weitzman (1976) result is that NNP(t) is on capital where capital is discounted future optimal consumption, the interest rate being the discount rate. There is then an attractive duality here: forward views of capital (discounted future optimal consumption programs at date t) coincide with backward views of capital (current value of accumulated stocks at date t). First we observe the Weitzman result as the solved Bellman equation in dynamic programming. This leads directly to the result that NNP(t) is interest on the value of accumulated capital. Next we re-work the derivations with an essential exhaustible resource and then with endogenously produced knowledge.