Equation Icon  D(L ) := {u ∈ C∞ (Ω ) : u(p) = 0 for all p ∈ Σ and u(p) ∈ V for all p ∈ 𝒯 }, n b T 0 p ∑ μ -∂u- Lu := A (t,x)∂x μ + B (t,x)u, u ∈ D(L ), μ=0