Improved Sobolev Embedding Theorems for Vector-valued Functions
  The aim of this paper is to give an extension of the improved Sobolev embedding theorem for single-valued functions to the case of vector-valued functions which is involved with the three-dimensional massless Dirac operator together with the three- or two-dimensional Weyl--Dirac (or Pauli) operator, the Cauchy--Riemann operator and also the four-dimensional Euclidian Dirac operator. 
Takashi Ichinose and Yoshimi Sait\=o
math-ph math.AP math.MP