The level 10 Fighter talent "Improved Knockdown" says "you automatically apply the critical success effect of a Trip", and the level 4 Rogue talent "The Harder They Fall" says "When you successfully Trip a flat-footed foe, your target takes 1d6 bludgeoning damage. On a critical success, the target takes 1d6 bludgeoning damage plus your sneak attack damage".
Is it possible to stack the effect of both talents?