OF, I. THIS PAPER ARE BEING STUDIED T. AND T.--H. INSTABILITIES OF SOLUTIONS FOR REACTION-- DIFFUSION SYSTEMS UNDER A CERTAIN TYPE OF NONSELFADJOINT BOUNDARY CONDITIONS. T. ROOT SUBSPACES OF THE L. OPERATOR PROVIDED WITH SUCH BOUNDARY CONDITIONS FORM A R. BASIS OF SUBSPACES; PERTURBATIONS., THAT ALLOWS THE STANDARD PROCEDURE FOR THE STUDY OF SPATIAL OR SPATIOTEMPORAL PATTERN FORMATION BY CONSIDERING THE UNSTABLE F. NORMAL MODES OF THE LINEARIZED. Turing and Turing--Hopf Instabilities in Certain Kind of a Nonselfadjoint Reaction--Diffusion System. Journal of Applied Nonlinear Dynamics, v. 14, n. 4, p. 887–898, 17 Aug.2026.