A quote from the Economist:
Part of this naturalistic approach is that the transistors in his systems often operate in what is known technically as the “sub-threshold domain”.
May we use a instead of the here and if no, why?
Google Books comes up with numerous examples of "known technically as a":
The sound of h (aitch) at the beginning of words such as have and house and in the middle of words such as ahead and behave is known technically as a voiceless glottal fricative.
(2008, R. Allen, "Pocket Fowler's Modern English Usage")
Are articles in this expression interchangeable? Or do they matter?