Correction to Byrnes-Gauger note

In Case 2, replace the line before "≥ 0" by
= {m_k + n_k - 2min(m_k, n_l)} + {m_k + n_k - 2min(m_l, n_k)}

= 2{m_k + n_k - (min(m_k, n_l) + min(m_l, n_k))} ≥ 0,

as min(m_k, n_l) ≤ m_k and min(m_l, n_k) ≤ n_k.

Last modified 15th May 2020