Davies–Dunkl

Davies & Petersen Inequality If a is a non-negative sequence, and p ≥ 1 then

Apn ≤ p n∑

akA p−1 k .

Reference Davies & Petersen [96].

de la Valle´e Poussin’s Inequality If on the interval [a, b] we have that

y′′ + gy′ + fy = 0, y(a) = y(b) = 0

then

1 < 2||g||∞,[a,b](b− a) + ||f ||∞,[a,b] (b − a) 2

2 .