Notation: the set of two-element subsets of $\Bbb N$
41899
Notation for: all subsets of size 2
148399
Two sets which contain each other as elements
132068
Write the set $\{1, 6, 11, 16,\ldots\}$ in compact (concise) notation.
50880
Expressing $\Bbb N$ as an infinite union of disjoint infinite subsets.
62255
Notation question: Subroup generated by two elements?
128966
Explicit bijection between $\Bbb R$ and permutations of $\Bbb N$
120610
Find a subset of $S = \{(1, 0, i), (i, 2, -3), (2-i, 1+i, i)\}$ that forms a basis for $\textsf V = \operatorname{span}(S)$
146204
Subsets sharing at most $i$ elements
36631
Is $[0,1] \cap \Bbb Q$ a compact subset of $\Bbb Q$?
5118
Show that $n ≤ 100$ if $ \{A_1,A_2,... ,A_n\}$ is a set of distinct $3$-element subsets of $\{1, 2,... , 36\}$ such that...
44214
The number of subsets of a set of cardinality $n$
126859
$\Bbb Z^\ast$ What is this notation?
111954
Computing the cardinality of a combinatorial set
139078
Infinite partition of $\mathbb N$ by infinite subsets
111032
Proof of Sets involving the Cartesian Product
18343
Counting homomorphisms between $\Bbb Z$ and $\Bbb Z_n$ and also between $\Bbb Z_n$ and $\Bbb Q$
146098
Number of nonempty subsets of a set with $n$ elements