In general ...

Consider the following clause :

H :- B1, B2, ..., Bm, !, Bn.

• Assume clause invoked by a goal G that matched H
• When cut encountered in the definition of H - the system has satisfied B1 to Bm
• The current solution to B1 to Bm is frozen, and all possible remaining alternatives are discarded
• The goal G becomes committed to this clause
• Any attempts to match G with the head of some other clause is precluded

C :- P, Q, R, !, S, T, U.
C :- V.
A :- B, C, D.

• Backtracking is possible within the goal list P,Q,R - BUT - as soon as the cut is reached, all alternate solutions of the goal list P,Q,R are suppressed
• The second C clause is also discarded
• Backtracking is however possible within S,T,U
• Cut is invisible from A - and only affects C