What is the reason behind calling $\emptyset$ improper subset of any non-empty set.?
97951
Is the void set (∅) a proper subset of every set?
272
Cantor Sets/nonempty/cardinality
46317
What is an Empty set?
56637
In naive set theory ∅ = {∅} = {{∅}}?
33064
Powerset of set with empty sets
11405
If a nonempty set of real numbers is open and closed, is it $\mathbb{R}$? Why/Why not?
47697
Russell's paradox: a set cannot contain its own powerset
62208
If $A$ is a non-empty set, then $A \notin A$
121847
Don't we need the axiom of choice to choose from a non-empty set?
122048
why is the set of all binary sequences not countable?
152354
Why is an empty set not a terminal object in categories $\mathsf{Top}$ and $\mathsf{Sets}$?
109219
How do the sets $\emptyset\times B,\ A\ \times \emptyset, \ \emptyset \times \emptyset $ look like?
9850
How many ways are there to choose 3 subsets $A,B,C$ of a set $\{1,2,3...n\}$ such that $ A \cap B \cap C = \emptyset $
112523
Does $\sqsubset$ have any special meaning?
150825
Is an empty set equal to another empty set?
124325
Element of, subset of and empty sets
36721
Is "The empty set is a subset of any set" a convention?