Show that $\{\emptyset,\{\emptyset\},\{\{\emptyset\}\},\{\{\{\emptyset\}\}\},...\}$ is a set
130418
Is ${\{\emptyset,\{\emptyset\},\{\{\emptyset\}\},\{\{\{\emptyset\}\}\},...\}} $ a set?
145865
Showing a set is an affine variety
120273
Showing that a collection of sets is a $\sigma$-algebra: either set or complement is countable
3072
If the empty set is a subset of every set, why isn't $\{\emptyset,\{a\}\}=\{\{a\}\}$?
17461
Show that a set is dense in $[-1,1]$
124325
Element of, subset of and empty sets
150825
Is an empty set equal to another empty set?
51687
Is the set $ \ (\mathbb{Z}_p \setminus \mathbb{Z}) \cap \mathbb{Q}$ non-empty?
65334
Show that a certain set is measurable
63529
How to show that this set is compact in $\ell^2$
87830
Relating the union of the power set of a set to the set itself
132382
Showing a set is nowhere dense in $C([0,1])$
146891
Why is $\{\emptyset\} \not = \emptyset$?
152354
Why is an empty set not a terminal object in categories $\mathsf{Top}$ and $\mathsf{Sets}$?
2935
Completness and Set of Result of One Set ?!?
22482
How can an ordered pair be expressed as a set?
75966
Prove that if $A$ is a set with $m$ elements, $B$ is a set with $n$ elements, and $A \cap B = \emptyset$, then $A \cup B$ has $m+n$ elements.