Range of a function: countable or not?
42794
Prove that functions map countable sets to countable sets
86004
Why are slice and range upper-bound exclusive?
76210
What does it mean if a Python object is "subscriptable" or not?
98151
Suppose that A is a countable set. Show that the set B is also countable if there is an onto function f from A to B.
23837
Why is $\mathbb{R}/{\sim}$ not first countable at $[0]$, where $x \sim y \Leftrightarrow x = y\text{ or }x,y \in \mathbb{Z}$?
102543
Real definition of "countable set"
155168
Is the collection of finite subsets of $\mathbb{Z}$ countable?
14235
count vs length vs size in a collection
136655
Find the range of the given function $f$
47637
Are strict local minima of a general function always countable?
151316
Is PHP's count() function O(1) or O(n) for arrays?
74709
How to elegantly check if a number is within a range?
28191
How to show that a set of discontinuous points of an increasing function is at most countable
52682
Is the power set of the natural numbers countable?
37637
Is "homework" countable?
68994
Countable closed sets
82837
Calculating limit of function