Heine's identity
= Heine's identity
{wiki=Heine's_identity}
Heine's identity is a mathematical identity related to sums of binomial coefficients. It is typically stated in the following form: \\\[ \\sum_\{k=0\}^n \\binom\{r\}\{k\} \\binom\{s\}\{n-k\} = \\binom\{r+s\}\{n\} \\\] for non-negative integers \\( r \\), \\( s \\), and \\( n \\).