Oscillation theorems for certain second order self-adjoint matrix differential systems

By means of generalized averaging pair technique and Riccati transformation method, oscillation criteria for self-adjoint differential matrix system of the form r(t)P(t)X (t ) + p(t)P(t)X (t )+ Q(t )F X (t ) G X(t) = 0 are obtained. This paper generalizes and improves the existing results including those obtained by Yang (2002), Li and Agarwal (2000) and Rogovchenko (1999).  2003 Elsevier Inc. All rights reserved