• 1 Overview
  • 2 Games, order, and surreal representatives ▶
    • 2.1 Finite games and birthdays
    • 2.2 The recursive order
    • 2.3 Surreal games
  • 3 Addition, negation, and surreal numbers ▶
    • 3.1 Addition and Negation on games
    • 3.2 Surreal Number
  • 4 Multiplication and the Conway induction ▶
    • 4.1 The recursive product
    • 4.2 A simultaneous well-founded proof
    • 4.3 Congruence and associativity
  • 5 The quotient ring and its order ▶
    • 5.1 Multiplication on equivalence classes
    • 5.2 Positive products and ordered-ring compatibility
  • Dependency graph

A Blueprint for Short Surreal Numbers in Lean

The surreal Lean project

  • 1 Overview
  • 2 Games, order, and surreal representatives
    • 2.1 Finite games and birthdays
    • 2.2 The recursive order
    • 2.3 Surreal games
  • 3 Addition, negation, and surreal numbers
    • 3.1 Addition and Negation on games
    • 3.2 Surreal Number
  • 4 Multiplication and the Conway induction
    • 4.1 The recursive product
    • 4.2 A simultaneous well-founded proof
    • 4.3 Congruence and associativity
  • 5 The quotient ring and its order
    • 5.1 Multiplication on equivalence classes
    • 5.2 Positive products and ordered-ring compatibility