Number9 Open Edition

What's a (natural) number? What does it look like? We represent numbers with symbols like 3, III, ٣ or Γ. We are aware of objects that have a numeric property: Squares have 4 sides. But, what about the number itself? What is it? What does it look like? In 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". 0 = {} 1 = { {} } 2 = {0, 1} = { {}, {{}} }, 3 = {0, 1, 2} = { {}, {{}}, { {}, {{}} } } ...and so on. Number9 is a creative interpretation of number 9, based...View all