The elliptic PDE −Δu = f on Ω (plus boundary data). Classical solvability via Green's functions; variational formulation via minimising ½∫|∇u|² − ∫fu in H¹₀.
The elliptic PDE −Δu = f on Ω (plus boundary data). Classical solvability via Green's functions; variational formulation via minimising ½∫|∇u|² − ∫fu in H¹₀.