sentences:  So
  
  where "N"0 is an isometric copy of "N" in "M".By assumption, it is also true that, "N", therefore "N"0, contains an isometric copy "M"1 of "M".Therefore one can write
  
  By induction,
  
  It is clear that
  
  Let
  
  So
  
  and
  
  Notice
  
  The theorem now follows from the countable additivity of ~.