## Linear linear progresion: 1,2,3,4,5,6,... foundation = number system, counting 2-1=3-2 --> the way we define numbers in the very first place (equal interval) ## Exp & Log Exponential growth, the power law, 各种定理, ... https://www.youtube.com/watch?v=JdhRD4TKh48 > 线形的另一端，是指数和对数 -- 两者同等重要的解释这世界的底层规律