Lorentz symmetry introduces an additional conformal structure, namely the set of lightcones (see the image on the left). For each event A, there is a set of events that can, in principle, either influence or be influenced by A via signals or interactions that do not need to travel faster than light (such as event B in the image), and a set of events for which such an influence is impossible (such as event C in the image). These sets are observer-independent.

Special relativity is defined in the absence of gravity, so for practical applications, it is a suitable model whenever gravity can be neglected. As gravity comes into play, assuming the universality of free fall, an analogous reasoning as in the previous section applies: there are no global inertial frames. Instead there are approximate inertial frames moving alongside freely falling particles; translated into the language of space-time: the straight time-like lines that define a gravity-free inertial frame are deformed to lines that are curved relative to each other, suggesting that the inclusion of gravity necessitates a change in spacetime geometry.

A priori, it is not clear whether the new local frames in free fall are indeed those in which the laws of special relativity hold – that theory, is based on the propagation of light, and thus on electromagnetism, and its preferred frames might not be the same as the local free-falling inertial frames. But using different assumptions about the special-relativistic frames (such as their being earth-fixed, or in free fall), one can derive different predictions for the gravitational redshift; the actual measurements show that free-falling frames in which light propagates as it does in special relativity. The generalization of this statement, namely that the laws of special relativity hold, to good approximation, in freely falling (and non-rotating) reference frames, is known as the Einstein [equivalence principle], and is one of the guiding principles when it comes to generalizing special relativistic physics to include gravity.

However, again with reference to experimental data, it becomes clear that, for instance, proper time for clocks in a gravitational field, is not measured by the Minkowski metric of special relativity. As in the Newtonian case, this is suggestive of a more general geometry: where all reference frames in free fall are equivalent, and approximately Minkowskian, we are dealing with a curved generalization of Minkowski space: instead of Minkowskian, assume the metric tensor to be, more generally, semi-Riemannian. Furthermore, each Riemannian metric is naturally associated with one particular kind of connection, a Levi-Civita connection; assume this to be the connection implied by the universality of free fall…

Get at me and let me know if that was it.

1) There are victims everywhere. Everyone’s being oppressed. So am I. But do I let it get to me? Oh no way! I’m way above that,and you should too.

2) The only way to rise out of your victimhood status is to beat your oppressors at their own game, show them you can make it big and flaunt your wealth. Then you can also show everyone that you weren’t really oppressed at all, only psychologically. There’s nothing wrong with the system. It’s just you.

3) Don’t talk about oppression. Live with what we have, which seems to work best for most people anyway, and shut the fuck up and take your angst someplace else.

http://www.nyupress.org/books/Living_Through_the_Hoop-products_id-5178.html

1) There are victims everywhere. Everyone’s being oppressed. So am I. But do I let it get to me? Oh no way! I’m way above that,and you should too.

2) The only way to rise out of your victimhood status is to beat your oppressors at their own game, show them you can make it big and flaunt your wealth. Then you can also show everyone that you weren’t really oppressed at all, only psychologically. There’s nothing wrong with the system. It’s just you.

3) Don’t talk about oppression. Live with what we have, which seems to work best for most people anyway, and shut the fuck up and take your angst someplace else.

p.s. for all dime readers: http://www.nyupress.org/books/Living_Through_the_Hoop-products_id-5178.html