The proof of Collatz problem: Construct the domain transformation: x = 3n + d, y = 3n-d, z = n / 2. 1. d = 0, n = 0, x = 3 × 0 + 0 = 0, y = 3 × 0-0 = 0, z = 0/2 = 0. 2. d = 1, n = 0, x = 3 = 0 + 1 = 1, y = 3 × 0-1 = -1, z = 0/2 = 0. 3. If d belongs to Z, n belongs to N+, x = 3 × 1 + d, y = 3 ×1-d, z=n/2; If d belongs to Z and n belongs to N-,x= 3× (-1) + d, y = 3 × (-1) -d, z = n / 2. (1) If d belo ... ...