elementary path problem

例句：

1. 1. The elementary path problem is a fundamentalconcept in physics.
   初级路径问题是物理学中的一个基本概念。
2. 2. The elementary path problemhas been studied extensively in the field ofquantum mechanics.
   在量子力学领域，初级路径问题已经得到了广泛的研究。
3. 3. Theelementary path problem is often used as astarting point for further research in the field.
   初级路径问题常常被用作进一步研究的出发点。