4 problems

A static perfect fluid solution is asymptotically flat if its spacetime approaches a flat spacetime at infinity, and it is spherically symmetric if it is invariant under rotations…

Let an asymptotically flat static perfect fluid spacetime be a solution satisfying the equations denoted by and. Fluid ball conjecture. Every such solution must be spherically symm…

Consider shear-free perfect fluids in general relativity, where rotation means nonzero vorticity and expansion means nonzero expansion scalar. Collins's conjecture. Shear-free perf…

Let a perfect fluid in general relativity have energy density $\mu$ and pressure $p$, with a barotropic equation of state $p=p(\mu)$ and $\mu+p\neq 0$. Let its velocity vector fiel…