Assume with Hotson that there is a negative energy sea with negative energy
> charges. I wonder whether, contrary to Hotson's wishes, a positive mass
> would nevertheless fall out of general relativity for such negative energy
> charges. Even weirder would be a negative mass. The weirdest of all,
> though, would be *no* mass.
If E = mc^2 is to remain an invariant, it would seem that Hotson must
either agree to negative mass:
(-E) = (-m)c^2,
or have another trick up his sleeve.