Homomorphisms between chevalley groups of types C_n AND G_2 over finite fields

摘要

It is known that there exists an isogeny sort of Chevalley groups G(∑,F) associated to any indecomposable root system ∑ and any field F. In this paper the author determines all nontrivial homomorphisms from G(∑,K) to G(∑, K) when the root system ∑ is of type C_n or G_2, and the fields k and K are finite fields of characteristic p.