Closure (闭包)

  • An property of a set whereby an operation on members of the set always produces a member of the same set
  • For example, Integers are closed under addition and multiplication like 1+1=2, where 2 is an integer (By closure of integers under multiplication and addition)

Commutativity (交换律)

  • The order in which the operands are taken does not affect the result of the operation
  • Addition & multiplication are commutative
  • x+y = y+x

Associativity (结合律)

  • Do not need to worry about the placement of parentheses in expressions with more than two operands
  • Addition & multiplication are associative

Distributivity (分配律)

  • Multiplication distributes over addition
  • x * (y + z) = (x * y) + (x * z)

Trichotomy (三分法)

  • For any two given inputs, there are exactly three possible outcomes. One of the outcomes must be true
  • x=y, x<y, x>y