I am wondering if the following argument is true: Let
Let $X$ be a $\dim n$ compact projective complex manifold, let $\alpha\in H^{2k}(X,\mathbb{Q})$$\alpha\in H^{2n-2}(X,\mathbb{Q})$ be a cohomology class. If for any ample line bundle $L$, we have $c_1(L)\cup \alpha=0$, can I argue that $\alpha=0$?