逆序数的计算及应用

逆序数在行列式的定义中起着非常重要的作用。而对于初学者而言,他们比较难理解逆序数的定义和计算排列的逆序数。特别是n阶排列的逆序数的计算。他们觉得异常的艰难。本文总结了从4个角度求逆序数的方法("左右后小"方法、"左右前大"方法、"右左前大"方法和"右左后小"方法)。方法的命名其实就是按照既定的顺序和大小的比较来进行,很好理解和掌握。并将这些方法应用于计算行列式。这对于学生理解逆序数和计算行列式具有重要的意义。

The inverse number plays a very important role in the def inition of determinant. For beginners, it is difficult for them to understand the def inition of reverse order and calculate the number of reverse orders. Especially the calculation of the inverse number of n order arrangement. They f ind it difficult. This paper summarizes the methods of solving inverse ordinal numbers from four perspectives ("left and right back small","left and right front big","right left front big" and "right left back small"). Method naming is actually in accordance with the established order and size of the comparison to proceed, a good understanding and mastery. These methods are applied to calculate determinants. This is of great significance for students to understand the number of inversion and calculate determinants.