Mathematicians Build Long-Awaited Graph Sandwich

Home Mathematicians Build Long-Awaited Graph Sandwich Comment Save Article Read Later Share Facebook Copied! Copy link Email Pocket Reddit Ycombinator Comment Comments Save Article Read Later Read Later graph theory Mathematicians Build Long-Awaited Graph Sandwich By Paulina Rowińska September 18, 2026

Save Article Read Later Kristina Armitage/ Quanta Magazine

combinatorics graph theory mathematics probability randomness All topics 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 computer science but difficult to analyze — by sandwiching it, in a mathematically rigorous way, between two simpler graphs.