Every well-ordered set is isomorphic to a unique ordinal
131163
There is a well ordering of the class of all finite sequences of ordinals
23442
Cardinality of the union of infinite and countable sets
6210
Countable compact spaces as ordinals
109054
Given an infinite set of cardinality $X$, is there a chain in $\mathcal P(X)$ of the same cardinalty of $\mathcal P(X)$?
118560
Ordered N-Tuples as Cartesian Products of Indexed Families
150719
All nonisomorphic trees of order $n$
72371
Proof of Strong Induction Using Well-Ordering Principle
59811
Finite Abelian groups with the same number of elements for all orders are isomorphic
86748
Isomorphism of hom sets implies objects are isomorphic
3217
Construction of uncountably many non-isomorphic linear (total) orderings of natural numbers
63489
The class of cardinal numbers is well ordered
38726
What set theory axioms do I need to believe in uncountable ordinals?
79734
Is every sub-lattice of $\mathcal P(X)$ isomorphic to a sub-lattice of $\mathcal P(X')$ containing singleton sets?
39880
Cardinality of Orderings of $\mathbb{R}$
138202
Every open set in $\mathbb{R}$ is a countable union of closed sets
138768
Showing that the family of Borel sets is countably generated
127200
Are there fields and ordered fields of every infinite cardinality?