Group homomorphisms from PSL_n(F) to PSL_m(K)

Let F and K be division rings,ChF be the characteristic of F,and n is a positive integer.GL_n(F) and SL_n(F) denote the general linear group and the special linear group of degree n over F,respectivly;PGL_n(F) and PSL_n(F) denote the projective general linear group and the projective special linear group of degree n over F,respectivly.When nm and F is a field,[2] determined the general form of group homomorphisms from PSL_n(F) to PSL_m(K).By using a method similar to those in [2] and [3],when nm,n≥3 and ChK=2 it is shown that every group homomorphism from PSL_n(F) to PSL_m(K) is trivial.