I've been trying to reconcile how the management trinity can have four components. I've concluded that there ARE only three parts, but one part has two subparts (like almost every other podcast where M&M joke about having 13 3/4 steps 8) ). They are:
3A. Delegation: Work Assignments (typically just called "Delegation")
3B. Delegation: Professional Development (typically just called "Coaching")
I've heard M&M mention how there's a fourth silent partner in the trinity. I think having a 3A and 3B gives that silent partner equal voice.
I hope I've helped anyone who was similarly confused by how 4=3 is a valid construct.