Conditions for the coincidence of the TFR, TRV and CE models

Bhattacharyya and Soejoeti (1989) put forward the tampered failure rate model (TFR Model) for step-stress Accelerated Life Tests(ALT). This paper studies the conditions for the coincidence of the TRV, TFR and CE models, gives the definitions of the coincidence, offers a proof of the necessary and sufficient condition for the coincidence of the TRV and TFR models in [1], and points out a mistake that appeared in the counterexample provided in [3].