Dear Eckard you write, " positive and negative de Broglie frequency and wavelength are mathematical artifacts". That may be true, but does not in any way illuminate the paradox of 'matter-waves' that is at the heart of many discussions here and the point to my last comment. There is nothing real about this view. Just more "mathematical artifacts" which you and I and others have been criticizing! (have I got that part wrong Eckard re:your criticisms?
In contrast to this sad state of affairs, 'growth and decay' is all real! No "mathematical artifacts" here! And that is what my derivation of the de Broglie frequency and wavelength reveal.
Your defense of Alan Kadin is admirable! I too support his questioning of the photon as particle. In fact, I mathematically prove in my Endnotes of my current essay the following proposition: "if the speed of light is constant, then light propagates as a wave". Perhaps you have disassociated from my essay before you reached that part!
Constantinos