68
DOC.
7
RELATIVITY LECTURE NOTES
[19]See
also
Vol.
4,
Doc.
1,
§§9,
10,
for
a more
detailed derivation of the Lorentz transfor-
mation.
[20]This approach
was
first
taken
by
Sommerfeld
(see Sommerfeld 1909).
[21]The
abbreviation
w
for the
quantity
2
V
2
C
already
occurs
in
Einstein's lectures
on
electricity
and
magnetism
in
winter
semester
1913/1914
(see
note
2 above).
[22]On
the
right-hand
side "t" and "x" should be
interchanged.
[23]"w'2"
should
be
"w"2."
[24]See
note 20.
[25]See
also the discussion of four-dimensional vector calculus
in Vol. 4,
Doc.
1,
[pp.
43-
54].
[26]In
the
expression
below, T
is
a
stress-energy tensor
and X is
the
x-component
of
an ex-
ternal force.
[27]Dual
six-vectors
are
denoted
by an
asterisk. See
also
Vol.
4,
Doc.
1, [pp.
55-56],
for
a
discussion of their
use
in
covariant
electrodynamics.
[28]The sign
of
"5-
"
should be minus.
(7^2
[29]The
signs
of the
components
in
the fourth
row
of the
array
should be minus.
[30]See
also the
analogous
discussion of the inertia of
energy
in Vol.
4,
Doc.
1,
§21.
[31]The
four
integrals
above
are
written
as
AI etc.,
with I
momentum
and E
energy.
[32]The
four
expressions to
the
right
of the vertical line
are
written
in
pencil.
30,