Proving a subset of the natural numbers has a minimal element
52861
Natural Numbers and Well ordering
118595
Proving that a set is countable by finding a bijection
84382
Sole minimal element: Why not also the minimum?
59535
Prove that there exists such a set of $n$ positive integers
66948
Proving question on sets
151928
How to prove that $N\setminus A$ is finite?
51649
prove there is no smallest positive rational number
86263
How do we show there are the same number of elements in each of the sets?
158882
Prove the existence of some weird family of sets
124890
Divisibility within a block of natural numbers
858
Is $\{\emptyset\}$ a subset of $\{\{\emptyset\}\}$?
33216
Prove that the order of an element in $S_n$ equals the least common multiple of the lengths of the cycles in its cycle decomposition.
20973
How can I find all the subsets of a set, with exactly n elements?
141895
Proving that a sequence is monotone
103744
Minimal $ab$ for Rational Number $a/b$ in an Interval
122271
A subset of a transitive set is transitive
40320
Suppose all the Associated Primes are Minimal.