Dear Steve Willner:

On Thursday, December 1, 2016 at 12:01:32 PM UTC-7, Steve Willner wrote:
In article ,
dlzc writes:
That is the case. =/= was intended to mean "not equal to".

I still don't know where you used = and where =/=.
That's a problem with using non-ASCII character
sets.

Sorry, but I *only* used ASCII character sets. I just presented it in a format you did not expect / decipher.

I said these things are exactly the same:
mass, rest mass, inertial mass, gravitational mass.
(you correct this more clearly below.)

I said this was not the same as mass:
relativistic mass (which Einstein said not to teach).

A quote from Taylor and Wheeler p. 256 may help:
The source of our difficulty is some confusion
between two quite different concepts: (1)
energy, the time component of the momentum-
energy 4-vector, and (2) mass, the magnitude
of this 4-vector.

Nowadays, physicists avoid confusion by using
"energy" when they mean (1). Terms used in the
past for this concept include "relativistic
mass," "inertial mass," "gravitational mass,"
and most regrettably, sometimes just "mass."
(T&W did this, though it's usually clear in
context which concept they meant.) Nowadays the
term "mass" is reserved for (2), but "rest mass"
or "proper mass" can be used if there's any
chance of confusion.

And is tantamount to a religious argument, with those that find no issue slinging relativistic mass around. Ignoring that it an infinite number for different scalar values, depending on in which axis a tiny bit of momentum might be applied, in relation to its line of motion.

If you want to discuss physics, please be
careful to use unambiguous terminology. In
particular, be careful to keep straight the two
concepts T&W described.

I find this harder and harder to do. Thanks.

David A. Smith