About author:BI Guang-qing(1958-), male, native of Mizhi, Shaanxi, a senior teacher(secondary school), engages in abstract operators; BI Yue-kai(1985-), male, native of Yan’an, Shaanxi, engages in radar signal processing and partial differential equations.
BI Guang-qing, BI Yue-kai. Abstract Operators and Higher-order Linear Partial Differential Equation[J]. Chinese Quarterly Journal of Mathematics, 2011, 26(4): 511-515.