Equation Icon  vtt = Δv + F (t,x), x ∈ Σ, t ≥ 0, (5.65 ) v(0,x ) = 0, v (0,x) = 0, x ∈ Σ, (5.66 ) t Lv = g(t,x), x ∈ ∂Σ, t ≥ 0, (5.67 )