Finding the Dominant Roots of a Time Delay System without Using the Principal Branch of the Lambert W Function

This brief note complements some results regarding a recently developed technique for the stability analysis of linear time-invariant, time delay systems using the matrix Lambert W function. By means of a numeric example, it is shown that there are cases for which the dominant roots of the system can be found without using the principal branch of this multi-valued function, contradicting the main proposition of the methodology.