... ConditionsAkbar B. Aliev1 and Ulviya M . Mamedova21Azerbaijan Technical University, AZ 1073, Baki, Azerbaijan2Institute of Mathematics and Mechanics of NAS of Azerbaijan, AZ 1141, Baku, AzerbaijanCorrespondence ... Equations. Ordinary and Partial Differential Equations,vol. 103 of Chapman & Hall/CRC Monographs and Surveys in Pure and Applied Mathematics,Chapman&Hall/CRC, Boca Raton, Fla, USA, 2000.8 ... nonlinear elastodynamics and general relativity,” Archive for Rational Mechanics and Analysis, vol. 63, no. 3, pp. 273–294, 1977.7 S. Yakubov and Y. Yakubov, Differential-Operator Equations....