The speed of light need not be constant
arXiv:gr-qc/0210066
Abstract
Recent observations of the fine structure of spectral lines in the early universe have been interpreted as a variation of the fine structure constant. From the assumed validity of Maxwell equations in general relativity and well known experimental facts, it is proved that and are absolute constants. On the other hand, the speed of light need not be constant.
3 pages revtex, comments welcome