Automorphisms Of The Nilpotent Subalgebra Generated By Positive Root Vectors Of The Chevalley Algebra Of Type C₄ Over Communicative Rings Of Characteristic 2

Let R be a communicative ring of characteristic 2 and 1 is the identity of R. Let N be the nilpotent subalgebra generated by positive root vectors of the chevaliey algebra of type C₄ over R. In this paper, we determine the automorphism group of N. We prove that any automorphism φ of N can be expressed as φ= ξ_b1,b2·ν_a·μ_b·σ·ω_d1,d2·d_x·η where ξ_b1,b2 ,σ,η,d_x are extremal, inner, central and diagonal automorphisms, respectively, of N, and v_a, μ_b, ω_d1,d2 are exceptional automorphisms.