Twin prime
Number theory
A prime that differs by 2 from another prime. The two together, such as 11 and 13, are called a twin prime pair.
What is usually left out
The twin prime conjecture asserts there are infinitely many such pairs and is open. Progress has been substantial without settling it: Zhang (2013) proved there are infinitely many prime pairs differing by at most some fixed bound, and collaborative work has since pushed that bound to 246. Getting it to 2 is the remaining problem.
Related terms
In the atlas
- Twin prime conjecture — Number theory, open