Fractional Triangle Decompositions in Graphs with Large Minimum Degree

Abstract

A triangle decomposition of a graph is a partition of its edges into triangles. A fractional triangle decomposition of a graph is an assignment of a nonnegative weight to each of its triangles such that the sum of the weights of the triangles containing any given edge is one. We prove that every graph on $n$ vertices with minimum degree at least $0.9n$ has a fractional triangle decomposition. This improves a result of Garaschuk that the same conclusion holds for graphs with minimum degree at least $0.956n$. Together with a recent result of Barber, Kühn, Lo, and Osthus, this implies that for all $\epsilon > 0$, every large enough triangle divisible graph on $n$ vertices with minimum degree at least $(0.9 + \epsilon)n$ admits a triangle decomposition.