Homework 4: Interior and Closure

Instructions. Assignments should be stapled and written clearly and legibly.

1. Section 2.1, #2.1(a)(b)(c), 2.2(b), 2.4, 2.12.
2. Consider \(\bR\) with topology \(\ct=\{\emptyset,\bR\}\cup \{(a,\infty):a\in\bR\}\).
   1. Give all closed sets of \((\bR,\ct)\).
   2. Find \(\overline{[4,8)}\), \(\overline{\{3,15,22,64\}}\), \(\overline{\{5,10,15,20,\ldots\}}\), and \(\{5,10,15,20,\ldots\}^{\circ}\).