Thank you! (Reads up on contravariance) The vectors are not what I thought they are (which was an ordered collection of number-things, btw, that cannot be any-variant) Another question then - is multiplication of co and contravariant vectors (vectors, not tensors) commutative? Because in school I learned that depending on order of column/row vectors you get inner or outer product, respectively XD And what is the difference between a tensor and particularly multidimensional matrix?
Back to relativistic bubbles
IIRC (I am very unsure) that energy variation is what blue/redshift is all about - for me, as a dabbling layman, lowering frequency is in many ways the same thing as making light slower, or stretching space a bit. When light exits gravitational well, it sheds energy, and with it, frequency, until, in case of black hole, it falls back down
Hmm, that actually makes sense, in a way - entering a bendalloy bubble is like falling down the grav well - you gain speed, and light gains intensity instead of frequency, resulting in the same energy gain... hmmm... Or does it gain frequency as far as outside world is concerned, but intensity compensation as far as the bubble itself is concerned? I've mentioned before that the way something perceives light kind of depends on the "speed" of its own interactions with said light - so they light might be blueshifted, but if you are sped up, you won't notice it. This can be made to fit a lot of things... except the air pressure thing At least I don't see how. ... I need to go to sleep NOW.