Can it be proven in ZF that $\mathbb{N}$ is a universal size comparator?
102202
The smallest infinity and the axiom of choice
149926
ZFC with class terms: is any set also a class?
19924
Uncountable ordinals without power set axiom
152613
Injection from $\mathbb{N}\to\{0,1\}$ to the set of all monotonic decreasing functions from $\mathbb{N}\to\mathbb{Z}$
104513
Order of elements in $Z_n$
139826
arbitrary large finite sums of an uncountable set.
97878
Are there uncountably many surjections from $\mathbb N$ to $\mathbb N$?
137982
Show that $\textbf{ZF}$ shows $\phi$ is $\Delta_1$
146062
A "Cantor-Schroder-Bernstein" theorem for partially-ordered-sets
63618
Can all ordinals be obtained by taking successors and countable limits?
152382
Can an infinite set A be larger than an infinite set B but still have the same cardinality?
70196
Is there any well-ordered uncountable set of real numbers under the original ordering?
83615
split conjugacy class in $S_n$ into two equal size conjugacy classes in $A_n$
11849
Size of a union of two sets
150140
Show that every nonzero integer has balanced ternary expansion?
60306
Natural class of functions whose $\mathcal O$-sets are linearly ordered
108957
Cardinality of a totally ordered union