1, the theory of six-degree space is a conjecture in the field of mathematics, also known as small-world phenomenon, small-world effect, small-world theory and six-degree division theory. According to the theory, there will be no more than six people between you and any stranger, that is to say, you can know any stranger through five middlemen at most.
2. The Ramsey model assumes that there are two inputs: capital K and labor L, and the production function is Q=Q(K, L). Without technological progress, the population remains unchanged, but the services provided can change. Output can be used for saving or consumption, and saving leads to investment and capital accumulation. Then: Q=C+S=C+K or C=Q(K, l)-K.
3. Both are sociological theories, one is more inclined to economics and the other is more inclined to management.