formally self-adjoint differential operator

例句：

1. 1.The formally self-adjoint differential operator is crucial for solving the problem.
   正式的自洽微分算子对于解决问题至关重要。
2. 2.In mathematics, the formally self-adjoint differential operator is a fundamental concept.
   在数学中，正式的自洽微分算子是一个基本概念。
3. 3. The formally self-adjoint differential operator was first introduced by Eduard Landau in 1928.
   正式的自洽微分算子最初由Eduardo Landau于1928年提出。