pp+2gap = 2
Number theory · Concept hub

Twin Prime Conjecture

1846 CE19th century (Polignac, 1846)

Concept

Are there infinitely many primes p with p+2 also prime? Formally conjectured by Polignac in 1846 — open for ~180 years. In 2013 Yitang Zhang proved the first finite-gap version.

Understand it in one breath

Primes thin out — yet do "tightly bound" pairs keep appearing? Astronomical twins like (10⁹⁹, 10⁹⁹+2) are still found. The answer feels like yes, but for ~180 years since Polignac's 1846 formal conjecture no one has proved it (Euclid proved only infinity of primes, never the twin-prime conjecture). In 2013 Yitang Zhang proved infinitely many primes lie within a finite gap — and that gap has since been compressed to 246.

At a glance

Year

Person

Proven gap

BCE 300

Euclid

Proved that there are infinitely many primes

1849

de Polignac

Formulated the twin prime conjecture (gap = 2)

2013.4

Yitang Zhang

Gap < 70,000,000 — the first finite bound

2013.11

Polymath8

Gap < 4,680

2014

Maynard·Tao

Gap < 246

Current

Still unsolved

The goal is to reach gap = 2

"From tens of millions to 246." One paper by Yitang Zhang in April 2013 ignited a field that had been stalled for centuries.

Key formula

#{p:p prime,  p+2 prime}=?\#\{p\,:\, p \text{ prime},\; p+2 \text{ prime}\} \stackrel{?}{=} \infty

Modern applications

Research on prime distribution, analytic number theory, and connections to the Riemann hypothesis.

Beyond MathVoyage

Loading…