- Comment Comments - Save Article Read Later Read Later ## Mathematicians Build Long-Awaited Graph Sandwich September 18, 2026 Kristina Armitage/Quanta Magazine ## Introduction Contributing Writer September 18, 2026 In 2004, two mathematicians hypothesized a powerful kind of sandwich. They were studying graphs, which are collections of points (called vertices) and lines (called edges). Graphs might represent anything from social groups to the internet to neurons in the brain. The mathematicians hoped to understand properties of one type of graph — a type that’s ubiquitous in mathematics and…