What is fork*-consistent on virtualchain?

I have some question:

  1. what is fork*-consistent on virtualchain?
  2. The virtualchain is blockchain agnostic, fork resistant, and portable. It follows the longest chain of the base blockchain as it is developed, ignoring transient forks.
    but, my question is :Must the longest chain be the main chain? if it is not main chain, how do?
  1. Fork*-consistent is a consistency model, formally described in this paper: http://www.scs.stanford.edu/~jinyuan/bft2f.pdf

  2. The main chain must be the valid chain with the most cumulative proof of work (the “longest” chain). Transient forks must be ignored, since no miners will build on top of them.