Our 班长 had invited a Lecturer to give a talk to our Lamrim Class.
The Lecturer opened the talk with a snippet on how Venerable Ru Jun had visited Singapore and given a discourse on 文殊三教授 - a teaching that is able to assist in the practice of 空性.
She related that the components of 文殊三教授 are:
I googled and found relevant text here:
It is the first time I have heard of 文殊三教授.
Contributing to this forum to see if any of us has anything to add.