Remarks on Blow up of Solutions of Nonlinear Wave Equations in Friedmann-Lemaître-Robertson-Walker Spacetime
摘要
Consider nonlinear wave equations in the spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) spacetimes. We improve some upper bounds of the lifespan of blow-up solutions for the power nonlinearity. We also show upper bounds of the lifespan in the critical cases for the time derivative nonlinearity.