I don't have any SR texts to hand, and was wondering if someone could prove the following conjecture:(adsbygoogle = window.adsbygoogle || []).push({});

all particles with positive rest-mass must move at speed less thanc.

I understand that there are a multitude of physical reasons that support the above conjecture. But is there a good (mathematical) reason why the boundary condition at [itex]\sigma = 0[/itex] (not [itex]\tau,[/itex] as that becomes a useless parameter in this case) the particle cannot be travelling atcalready?

Thanks in advance.

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# Massive particles in SR

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