fourth-order problem 四阶问题

fourth order obstacle problem 四阶障碍问题

fourth-order boundary value problem 四阶边值问题

singular fourth-order boundary value problem 奇异四阶边值问题

nonlinear fourth-order boundary value problem 非线性四阶边值问题

fourth-order two-point boundary value problem 四阶两点边值问题

fourth-order eigenvalue problem 四阶特征值问题

fourth order boundary value problem 四阶边值问题