Pentcho Valev wrote:
A. Einstein, "Relativity", Chapter 22:
"A curvature of rays of light can only take place when the velocity of
propagation of light VARIES with position."

So, according to Einstein, an observer positioned in a gravitational
field will measure a VARIABLE, not constant velocity of light.

No, he did NOT say that. He said what he said. shrug

But indeed, when an observer measures (say) the deflection of stars'
images during an eclipse, that observer can conclude that the presence
of the sun's gravitation did affect the propagation of light from those
stars, and that means a position-dependent variation in speed
(necessarily over the different non-local paths from star to observer).


The
observer can measure, for instance, the frequency shift and, if
Einstein is right, a non-zero frequency shift corresponding to the
changing velocity of light will be detected.

Hmmm. For the case of observing stars' images before, during, and after
an eclipse, the change in frequency is higher order in (extremely) small
quantities than the deflection. I'm pretty sure it is well below
realistic experimental resolutions.


Einsteinians never discuss this problem voluntarily

This is not a "problem", it is merely your personal misconceptions and
errors.


Sam Wormley wrote:
Valev confuses *velocity* of light with *speed* of light!

AFAIK Einstein basically thought in German, which does not have
different words for "speed" and "velocity" ("die Geschwindigkeit" is
used for both). Certainly his "velocity of propagation" could be phrased
as "speed of propagation" without changing the underlying physics. While
Valev is indeed confused, I don't think this is relevant.


Tom Roberts