W^{k,p}(ℝ^n) embeds into L^q for 1/q = 1/p − k/n (when positive), or into C^{k−[n/p], α} when k>n/p. Backbone of elliptic regularity and nonlinear PDE.
W^{k,p}(ℝ^n) embeds into L^q for 1/q = 1/p − k/n (when positive), or into C^{k−[n/p], α} when k>n/p. Backbone of elliptic regularity and nonlinear PDE.