Title: Daniel's Flashcards / Year 4 / Term 1 / Additive Combinatorics

html: Definition 1.15. Given A , B ⊆ G we define the additive energy between A and B to be
E ( A , B ) = | { ( a , a ′ , b , b ′ ) ∈ A × A × B × B : a + b = a ′ + b ′ } | .
We refer to the quadruples ( a , a ′ , b , b ′ ) such that a + b = a ′ + b ′ as additive quadruples.