Carving
When he is carving he is riding the sidecut of the ski. So his only movement to turn is to tip his skis on edge and move over his skis with his body to stay dynamically balanced. And his only movement at transition is to see that his upper body transits from one side to the other in a balanced state of being. The turns are therefore longer and his upper body movements more lateral. He is laying down some good angles. He is going very fast. No braking. Controlling his speed by pointing his skis out of the fall line. The tighter he manages to carve his turns the less he will be accellerating down the fall line and the more controll he has of his speed. Only works to a sertain limit and takes a lot of muscle effort to do for a longer period of time if the slope is steep.
Pivotted
When he is pivotting he is over-riding the skis natural turn radius. Linking very short turns closer to the fall line with a pivotted turn entry and a hard edge set in the belly of the turn. He stays more upright with lower edged angles. This kind of turning is only possible if you get the kind of rebound he is getting at the end of the turn. His turns are in other words feeding on rebound and making use of up-unweighting. Some would call it down-unweighting but that is only a matter of how you look at it. Main thing is that his mass is being pushed up so that he can retract his skis and float through the transition. By tightening his turn radius and ramping up his rhythm he can gain more controll over his speed. This kind of turn is often refered to as a SL turn but in ski racing there is no difference between SL and GS. Both diciplines foundation block is carving.
Pivot = turn your skis. Carving = let the skis turn you.
A pivot is usually caused by femure rotation while a carved turn is produced by tipping the ski on its edge