We prove the equality of two canonical bases of a rank 2 cluster algebra, the greedy basis of Lee–Li–Zelevinsky and the theta basis of Gross–Hacking–Keel–Kontsevich.National Science FoundationThis is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jcta.2016.08.00
