Question 1
What is the derived set of a subset $A$ in a topological space?
Question 2
In many standard settings, which description matches a limit point of a set $A$?
Question 3
Which statement is always true about the derived set of a set $A$?
Question 4
If a point $x$ is isolated in a set $A$, what can be said about $x$ and the derived set of $A$?
Question 5
Which set has an empty derived set in the usual topology on the real line?
