Oh ! if you never heard of such a thing it must be pseudoscience or something.
Thanks for clearing it out, and sorry for wasting your precious time.
So speed of light is always constant in vacuum as Einstein assumed, and the famous 4 equations of Maxwell are the ones that he actually published, understood.
I am just saying that I have never heard of that. Maybe if you could share more information, I will be able to tell you more. It is also possible that what you mention is a rephrasing or what is usually known with 4 equations.
And by the way, you are not wasting my time. I am very happy to help and it is actually my pleasure.
If you are curious I ll save you a quick google
Following article says speed of light is a limit rather than a constant (in vacuum)
https://www.sciencenews.org/article/speed-light-not-so-constant-after-all
Also quantum entanglement of photons, which somehow could be seen as faster than speed of light as described in the following link:
http://www.foxnews.com/tech/2017/07/11/space-breakthrough-scientists-teleport-photon-from-earth-to-orbit.html
For the quantum entanglement stuff: no, there is nothing going faster than light. "They could be seen" means "some journalist sees it". This is not what it is. Both photons travel at the speed of light. Period.
The first article is indeed interesting. I didn't know about it and it is right. Thanks for sharing. There are cases where light can indeed be slower even in the vacuum.
Actually, special relativity says that there is a speed limit, nothing more.