ABSTRACT

Given a function f : Ω ⊂ RN →R, with N sufficiently high natural number, we say ‘partial differential equation of order n′, an equation of the form: () f ( x 1 , …. , x m , u , ∂ u ∂ x 1 , ….. , ∂ u ∂ x m , ….. , ∂ n u ∂ x 1 n , ….. , ∂ n u ∂ x m n ) = 0 , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429027758/54c591ad-2711-4f9d-817f-8d47de88d0f1/content/eq401.tif"/>