By investigating the intersection numbers , some necessary conditions are gotten 中的一個差集,通過考察相交數,得到一些
百科解釋
In mathematics, and especially in algebraic geometry, the intersection number generalizes the intuitive notion of counting the number of times two curves intersect to higher dimensions, multiple (more than 2) curves, and accounting properly for tangency. One needs a definition of intersection number in order to state results like Bézout's theorem.