Rainbow numbers of $[m]\times [n]$ for $x_1+x_2=x_3$

Kean Fallon, Ethan Manhart, Joe Miller +3

Consider the set $[m]\times [n]=\{(i,j):1\le i\le m,1\le j\le n\}$ and the equation $x_1+x_2=x_3$, namely $eq$. The \emph{rainbow number of $[m]\times [n]$ for $eq$}, d…