- There are an infinite number of primes p such that p+2 is also prime.
This conjecture has been researched by many number theorists. The majority of mathematicians believe that the conjecture is true. In 1966, Chen showed that there are an infinite number of primes p such that p+2 is a product of at most two prime factors. The approach he took involved a topic called Sieve Theory, and treated the Twin Prime Conjecture and Goldbach's conjecture in similar manners.