Lebesgue measure

• What Is the Difference Between Lebesgue-Null and Jordan-Null Sets?
  Lebesgue-null sets admit countable covers of arbitrarily small total volume; Jordan-null sets require finite covers, so boundedness alone does not make them equivalent.
• Is the Function Definition with 9^n Well-Defined?
  The formula is incomplete unless n is specified. If n is fixed, the function is measurable and its Lebesgue integral on [0,1] is 9^n.