1. What?
   1. relationships between
      1. changes in # of inputs
      2. change in production
2. Examples
   1. output doubles
      1. constant Returns to scale
      2. LRAC unchanged
   2. output more then doubles
      1. increasing returns to scale
      2. LARC falling
   3. output less then doubled
      1. decreasing returns to scale
      2. LRAC rising