On the topological decomposition of the hypersurfaces in projective toric manifolds

Abstract

In this paper, we want to discuss the topology of the non-singular hypersurface $Y^n$ with complex dimension $n$ in a projective toric manifold $X^{n+1}$. When $n$ is odd, our main results are a decomposition of $Y^n\cong Y^{\prime }♯s(S^n\times S^n)$ as a connected sum of $s$ copies of $S^n\times S^n$ with a differential manifold $Y^{\prime }$ such that $b_n(Y^{\prime })=0$ or 2. When $n$ is even and the degree of $Y$ in $X$ is big enough, we find that $Y$ also admits such a decomposition $Y^{\prime }♯s(S^n\times S^n)$, where $Y^{\prime }$ satisfy $b_n(Y^{\prime })-|sign(Y^{\prime })|=b_n(X)\pm sign(H^n(X))$, where $sign(H^n(X))$ is the signature of a certain bilinear form defined on $H^n(X,\mz)$.

arXiv comment15 pages