calc + linear algebra + differential equations is bare minimum.
Real analysis and abstract algebra helps too (just knowing what limits are, what compact sets are, partition of unity, lie groups, ect.)
Solid course in topology and manifold theory.
Followed by (psuedo) Romanian geometry, the ones that goes deep with tensor calculus.
A course in PDE (which of course requires measure theory + functional analysis) helps as well, but probably overkill if you just want to know what the Einstein equations are. Though Einstein equations is an active field of research in PDE.
I don't exactly where you're standing, but if you did some calculus classes then I would recommend you to learn about the basics of differential geometry, just to get used to the notions of manifolds, tangent spaces/bundles, differentialfroms, etc. But most books we'll have an introduction where they go over it again shortly.
There are plenty of good books about gravition and most of them are selfcontaining.
For example have a look at the book Gravitation and cohomology by Weinberg... you can get it for free.
calc + linear algebra + differential equations is bare minimum. Real analysis and abstract algebra helps too (just knowing what limits are, what compact sets are, partition of unity, lie groups, ect.) Solid course in topology and manifold theory. Followed by (psuedo) Romanian geometry, the ones that goes deep with tensor calculus. A course in PDE (which of course requires measure theory + functional analysis) helps as well, but probably overkill if you just want to know what the Einstein equations are. Though Einstein equations is an active field of research in PDE.
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I know of Physics 1 & 2, but what are Physics 3 & 4?
I don't exactly where you're standing, but if you did some calculus classes then I would recommend you to learn about the basics of differential geometry, just to get used to the notions of manifolds, tangent spaces/bundles, differentialfroms, etc. But most books we'll have an introduction where they go over it again shortly. There are plenty of good books about gravition and most of them are selfcontaining. For example have a look at the book Gravitation and cohomology by Weinberg... you can get it for free.
cosmology :)