Representations of Spin(4), Spin(2,2) and Spin(3,1)
  In this essay we present an outer product on R^6, and we show that R^6 with this outer product can take three kinds of Lie brackets. We prove that R^6 with these Lie brackets take the structures of so(4), so(2,2) and so(3,1). We also deduce a 4-dimensional submanifold of R^6 with an almost complex structure. 
Ali Delbaznasab, MohammadReza Molaei
math-ph math.MP