Erdős Problem 560

### What is the conjecture

https://www.erdosproblems.com/560

Let $\hat{R}(G)$ denote the size Ramsey number, the minimal number of edges $m$ such that there is a graph $H$ with $m$ edges such that in any $2$-colouring of the edges of $H$ there is a monochromatic copy of $G$.

Determine
$$\hat{R}(K_{n,n}),$$
where $K_{n,n}$ is the complete bipartite graph with $n$ vertices in each component.

Status: open

### Choose either option
- [ ] I plan on working on this conjecture
- [x] This issue is up for grabs: I would like to see this conjecture added by somebody else