General-relativistic thin-shell Dyson megaspheres

Loosely inspired by the somewhat fanciful notion of detecting an arbitrarily advanced alien civilization, we consider a general-relativistic thin-shell Dyson mega-sphere completely enclosing central star-like object, and perform full analysis using Israel--Lanczos--Sen junction conditions. We focus attention on surface mass density, stress, classical energy conditions, forces between hemispheres. find that in physically acceptable region NEC, WEC, SEC are always satisfied, while DEC can be violated if is sufficiently close to forming black hole. also demonstrate original quasi-local version maximum force conjecture, F <= {1/4} F_{Stoney} = F_{Planck}, easily compact, is, Interestingly there finite parameter space where one violate conjecture without violating DEC. Finally, very briefly discuss possibility nested mega-spheres (Matrioshka configurations) thick-shell mega-spheres.