Find a bijective function that maps integers to rationals $f: \Bbb Z\rightarrow \Bbb Q$
5803
Produce an explicit bijection between rationals and naturals?
124374
A bijective function between a square and its side
21391
Proving Functions are Surjective
5375
Is there a bijective function mapping Natural numbers to Natural numbers, other than $f(n) = n$?
41593
Use of Bijection for computation
6171
Isomorphism between $\Bbb{Z}[\sqrt{d}]$ and a quotient of $\Bbb{Z}[X].$
37219
Quadratic Integers in $\mathbb Q[\sqrt{-5}]$
38257
Continuous bijection from $(0,1)$ to $[0,1]$
158309
Find a function that is continuous only on rationals
34998
How to prove that $\mathbb{Q}$ ( the rationals) is a countable set
19019
Find all functions $f:\Bbb{Q}\rightarrow \Bbb{Q}$ such that $f(x)+f(t)=f(y)+f(z)$ for all rational numbers $x<y<z<t$ that form an AP
39642
Efficient way to find $[\mathbb{Q}(\sqrt{5}, \sqrt{3}, \sqrt{2}): \mathbb{Q}(\sqrt{3}, \sqrt{2})]$
82559
Showing two ring homomorphisms that agree on the integers must agree on the rationals
18343
Counting homomorphisms between $\Bbb Z$ and $\Bbb Z_n$ and also between $\Bbb Z_n$ and $\Bbb Q$
72642
Continuous bijection from $(a,b) \to S^1$?
14322
Examples of bijective map from $\mathbb{R}^3\rightarrow \mathbb{R}$
124847
Is the set of surjective functions from $\mathbb{N}$ to $\mathbb{N}$ uncountable?