0x8b0573d1…eb51sent to0x192ce826…46af·#16,554,715·view on Etherscan
What's a (natural) number? What does it look like?\n\nWe represent numbers with symbols like 3, III, ٣ or Γ.\n\nWe are aware of objects that have a numeric property: Squares have 4 sides.\n\nBut, what about the number itself? What is it? What does it look like?\n\nIn 1923, John von Neumann proposed a set-theoretic construction of natural numbers: We can start with the empty set to represent 0, and then create each next object as the set containing all previous numbers. In a way, creating every natural number, a whole universe, out of \"empty\".\n\n0 = {}\n1 = { {} }\n2 = {0, 1} = { {}, {{}} },\n3 = {0, 1, 2} = { {}, {{}}, { {}, {{}} } }\n...and so on.\n\nNumber9 is a creative interpretation of number 9, based on von Neumann's construction. Each closed shape is a set. Empty circles are empty sets. Think of it as 9's blueprint: An elegant, simple and easy to understand construction with fractal properties.\n\nNumber9 an open edition accessible to everyone. Let's spread an idea worth spreading beyond mathematicians.\n\nTwo/wallet = gift one to a friend. Distributed under CC0.