Motivated by Koll\'{ a}r-Matsusaka's Riemann-Roch type inequalities, applying effective very ampleness of adjoint bundles on Fujita conjecture and log-concavity given by Khovanskii-Teissier inequalities, we show that for any partition $\lambda$ of the positive integer $d$ there exists a universal bivariate polynomial $Q_\lambda(x, y)$ which has deg $Q \leq d$ and whose coefficients depend only on $n$, such that for any projective manifold $X$ of dimension $n$ and any ample line bundle $L$ on $X$, \begin{ equation*} \left|c_\lambda(X)\cdot L^{ n -d}\right|\leq \frac{ Q_{ \lambda}(L^{ n}, K_X \cdot L^{ n -1} )}{ (L^{ n})^{ d-1}}, \end{ equation*} where $K_X$ is the canonical bundle of $X$ and $c_\lambda(X)$ is the monomial Chern class given by the partition $\lambda$. As a special case, when $K_X$ or $-K_X$ is ample, this implies that there exists a constant $c_n$ depending only on $n$ such that for any monomial Chern classes of top degree, the Chern number ratios \begin{ equation*} \left|\frac{ c_\lambda(X)}{ c_1 (X) ^{ n}}\right|\leq c_n, \end{ equation*} which recovers a recent result of Du-Sun. The main result also yields an asymptotic version of the sharper Riemann-Roch type inequality. Furthermore, using similar method we also obtain inequalities for Chern classes of the logarithmic tangent bundle.
Categories: math.AG math.DG