  In the AdS_5/CFT_4 set-up, extremal three-point functions involving two giant
1/2 BPS gravitons and one point-like 1/2 BPS graviton, when calculated using
semi-classical string theory methods, match the corresponding three-point
functions obtained in the tree-level gauge theory. The string theory
computation relies on a certain regularization procedure whose justification is
based on the match between gauge and string theory. We revisit the
regularization procedure and reformulate it in a way which allows a
generalization to the ABJM set-up where three-point functions of 1/2 BPS
operators are not protected and where a match between tree-level gauge theory
and semi-classical string theory is hence not expected.
