We choose $I = [-1,1]$ and fix any very good extremal pair $(Q, R)$. We set $P = QR$. Show that $P$ satisfies the differential equation: $$\|P\|_I^2 - P^2 = \frac{1}{(n+m)^2}\left(1 - X^2\right)P'^2$$
We choose $I = [-1,1]$ and fix any very good extremal pair $(Q, R)$. We set $P = QR$. Show that $P$ satisfies the differential equation:
$$\|P\|_I^2 - P^2 = \frac{1}{(n+m)^2}\left(1 - X^2\right)P'^2$$