标题： 多射影丛的同构与射影塔 显示英文标题

标题： Isomorphism of Multiprojective Bundles and Projective Towers

摘要： 我们研究在什么情况下两个不同维数的光滑射影代数簇上的射影丛可以同构。 我们证明了在不同的射影空间上的多射影丛（射影丛的纤维积）不能同构，除非在平凡的情况下。 我们还在一定假设下，给出了两个高度为3的射影丛塔的顶簇同构的充要条件。 显示英文摘要

摘要： We study when two projective bundles over two arbitrary smooth projective varieties of different dimensions can be isomorphic. We show that two multi-projective bundles (fibre product of projective bundles) over different projective spaces cannot be isomorphic, except in the trivial case. We also give necessary and sufficient conditions for the top varieties of two height 3 towers of projective bundles being isomorphic, under certain assumptions.