01 · The idea
In everyday language
Look for primes among numbers with one fixed remainder modulo q. For a remainder coprime to q, a natural main term predicts how primes should be distributed. The error is difficult to control uniformly for every modulus. The Bombieri–Vinogradov theorem, proved independently by Bombieri and Vinogradov, gives strong bounds after averaging over a substantial range of moduli. Large-sieve estimates are central to this approach. Averaging does not make each error disappear; it limits how large the collection of discrepancies can be and supplies a powerful substitute for some unavailable individual estimates.
Why it matters
Average distribution results became essential tools for studying primes and related arithmetic patterns, demonstrating that collective control can unlock problems beyond current pointwise bounds.

