Picone's formula for linear non-selfadjoint impulsive differential equations

In this paper, we derive a Picone type formula for second-order linear non-selfadjoint impulsive differential equations having fixed moments of impulse actions, and obtain a Wirtinger type inequality, a Leighton type comparison theorem, and a Sturm–Picone comparison theorem for such equations. Moreover, several oscillation criteria are also derived as applications.