====== HW 5 ======
Since we had a midterm this week, and did not cover much material, this homework is relatively short. 
It will be based on first half of Ross section 13. {{ math104-s21:rudin_ch2.pdf |Rudin's chapter 2}} also has a nice exposition, about metric space and topology.

  * Ex 13.3, 13.4, 13.6, 13.7 
  * Read Rudin Ch 2, on countable set, metric space and topology.