# Gaps between primes and almost primes. Patterns in primes and almost primes. Approximations to the twin prime and Goldbach conjectures (PRIMEGAPS) Start date: Nov 1, 2008, End date: Oct 31, 2013 PROJECT  FINISHED

"The twin prime conjecture, that n and n+2 are infinitely often primes simultaneously, is probably the oldest unsolved problem in mathematics. De Polignac (1849) conjectured that for every even value of h, n and n+h are infinitely often primes simultaneously. These are the most basic problems on gaps and patterns in primes. Another one is the conjecture of Waring (1770), stating that there are arbitrarily long arithmetic progressions (AP) of primes. For the newest developments we cite Granville (Bull. AMS 43 (2006), p.93): ): Despite much research of excellent quality, there have been few breakthroughs on the most natural questions about the distribution of prime numbers in the last few decades. That situation has recently changed dramatically with two extraordinary breakthroughs, each on questions that the experts had held out little hope for in the foreseeable future. Green and Tao proved that there are infinitely many k-term arithmetic progressions of primes using methods that are mostly far removed from mainstream analytic number theory. Indeed, their work centers around a brilliant development of recent results in ergodic theory and harmonic analysis. Their proof is finished, in a natural way, by an adaptation of the proof of the other fantastic new result in this area, Goldston, Pintz and Yildirim s proof that there are small gaps between primes. The proposal's aim is to study these types of patterns in primes with possible combination of the two theories. We quote 3 of the main problems, the first one being the most important. 1) Bounded Gap Conjecture. Are there infinitely many bounded gaps between primes? 2) Suppose that primes have a level of distribution larger than 1/2. Does a fixed h exists such that for every k there is a k-term AP of generalised twin prime pairs (p, p+h)? 3) Erdôs' conjecture for k=3. Suppose A is a sequence of natural numbers, such that the sum of their reciprocals is unbounded. Does A contain infinitely many 3-term AP's?"