We prove that the inhomogeneous estimate of vector fields on balls in R n B |D k−1 u| n/(n−1) dxholds if and only if the linear, constant coefficient differential operator A of order k has finite dimensional null-space (FDN). This generalizes the Gagliardo-Nirenberg-Sobolev inequality on domains and provides the local version of the analogous homogeneous embedding in full-spaceproved by Van Schaftingen precisely for elliptic and cancelling (EC) operators, building on fundamental L 1 -estimates from the works of Bourgain and Brezis. We prove that FDN strictly implies EC and discuss the contrast between homogeneous and inhomogeneous estimates on both algebraic and analytic level.2010 Mathematics Subject Classification. Primary: 46E35; Secondary: 26D10.provided that A is EC and u ∈ C ∞ (Ω, V ) satisfy B j u = 0 on ∂Ω, where B j is a (finite collection of) linear differential operator(s) defined on ∂Ω that satisfy the Lopatinskiȋ-Shapiro Complementing Conditions. Such a result would provide a reasonable analogue of the results in [33,1,2,27] to the case p = 1, in spite of Ornstein's Non-inequality. The aim of this paper is to confirm this expectation in the case when B j ≡ 0 ("no boundary condition") and Ω is a ball (whereas Van Schaftingen's result [56, Thm. 1.3] essentially deals with the antipodal case when B j = ∂ j ν , j = 0 . . . k − 1, i.e., "all boundary conditions"). We emphasize that in the present situation the geometry of ∂Ω is not the foremost problem, as is the extendibility of functions u : Ω → V to some v : R n → V while ensuring that Av ∈ L 1 (R n , V ) boundedly. In fact, as we shall see below, this property