Gene Fuller wrote:
You appear to use a very precise, quantitative definition of
"interference." I do not recall ever seeing such a quantitative
definition. Could you please give us a reference or an exact quote from
some reasonably reputable source that defines "interference" in a
quantitative and unambiguous manner?

I've already posted what Eugene Hecht said about interference.

In the irradiance (power density) equation,
Ptot = P1 + P2 + 2*SQRT(P1*P2)cos(A)
the last term is known as the "interference term", page 388 of
"Optics" by Hecht. Here's another reference:

http://en.wikipedia.org/wiki/Interference

A Google search for "electromagnetic wave interference" yielded
1,650,000 hits.

You imply that some interactions lead to "interference" and some do not.
How can the unwashed among us know when the magic occurs and when it
does not?

If the interference term in the above irradiance (power
density) equation is not zero, then interference is present.

In the s-parameter equation, b1 = s11*a1 + s12*a2, if b1
equals zero while s11, a1, s12, and a2 are not zero, then
total destructive interference is present.

Assume we superpose two coherent, collinear voltages, V1 and V2:

If (V1+V2)^2 V1^2+V2^2, then constructive interference is
present.

If (V1+V2)^2 V1^2+V2^2, then destructive interference is
present.
--
73, Cecil http://www.w5dxp.com