The study of global solvability and hypoellipticity of differential operators on manifolds has attained increasing prominence over recent decades. At its core, global solvability investigates the ...

We prove lower bounds for the fundamental solutions of the non-divergence form operators $\sum _{i,j}a_{i,j}(x,t)X_{i}X_{j}-\partial _{t}$ and $\sum _{i,j}a_{i,j}(x)X ...