Asked to Google:
What is x' in Einstein's derivation of Lorentz transforms?
Answer from Google AI (which is a resume of many documents):
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AI Overview
In Einstein's derivation of the Lorentz transformations, "x'" represents
the position of an event as measured in a moving reference frame
(denoted as S'), while "x" represents the position of the same event in
a stationary reference frame (S); essentially, it's the transformed
x-coordinate in the moving frame, taking into account the relative
velocity between the two frames.
Key points about x':
Relative to x:
"x'" is related to "x" through the Lorentz transformation equation,
which includes the relative velocity (v) between the reference frames
and the Lorentz factor (γ).
Interpretation:
If an event occurs at position "x" in the stationary frame, "x'"
indicates where that same event would be observed in the moving frame.
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Also: Galilean transform in Einstein's paper:
http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/ltrans.html-------------------------------------------------------------------
NOW, WHAT ABOUT THIS PAPER?
Einstein’s Derivation of the Lorentz Transformations
in the1905 Paper is Internally Inconsistent
Jon C. Freeman
https://www.nikhef.nl/~h02/deriv_lt_freeman.pdfCONCLUSION
The results of the analysis show that the derivation given in
the 1905 paper is invalid. It is flawed for several reasons.
The most serious is the contradictory requirement that the
partial of τ with respect to x´ must be zero to arrive at the
partial differential equation for determining τ.
But the solution for τ from that equation does not allow this
to be the case. The only way it could be satisfied is for v
to be zero. Another problem is that with a Taylor expansion
attempting to get the defining partial differential equation,
one must divide by x´ while starting with x´ equal to zero.
A third problem is the inconsistent reassignment of independence
and dependence between the three variables x, t, and x´.
The derivation starts with x and t as independent, then defines
x´ as being dependent on both. Then later treats x´ and t as
independent so x is then dependent. Later after determining
τ(x´,t) he writes x´ in its original form and goes back to x
and t being independent. The reason for this switching back
and forth is supposedly justified by stating that in some places
in the derivation one is following a fixed point, while in others one
is no longer doing that. Another problem is the interpretation of x´...
[THE CONCLUSION IS LARGER THAN THIS EXCERPT]
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I'm done with this thread. Those who deny accepting the truth of this
invalid derivation of Lorentz are biased ignorants beyond repair.
Relativity is a pseudoscience that gain control of the ability to reason
for those "Einstein's zombies" with no brain. Freaks possessed with
Einstein's demons, that have a herd mentality. Poor people.