\documentclass[11pt]{uebung-e} %\usepackage{diagrams} %\usepackage{mathtools} \newcommand{\rarr}{\rightarrow} \usepackage{enumerate} \usepackage{diagrams} %\renewcommand{\d}{\text{d}} %\newcommand{\e}{\text{e}} %\renewcommand{\i}{\text{i}} \newcommand{\rtf}[2]{\ensuremath{\theta\left[\begin{array}{c}#1\\#2\end{array}\right]}} \begin{document} \vorlesungA{D-MATH}{FS 2016}{Prof.~Peter S. Jossen}{Complex Abelian Varieties}{Exercise Sheet}{8} \begin{aufgaben} %\item \input{q_4.tex} \item \input q_1.tex \item \input{q_3.tex} %%\input a_1.tex %%\pagebreak %\item (\emph{Morphisms to $\mathbb{P}^N$})\footnote{For a more general treatment, see R. Hartshorne, \emph{Algebraic Geometry}, II, Theorem 7.1.} Let $X$ be a complex variety \textcolor{red}{or maybe complex manifold?}. Show: %\begin{unteraufgaben} %\item If $\varphi:X\lra \mathbb{P}^N$ is a morphism of \textcolor{red}{what?}, then $\varphi^*(\mathcal{O}(1))$ is a line bundle on $X$, generated by the global sections $\varphi^*(x_0),\dotsc,\varphi^*(x_N)$. %\item Conversely, if $\mathcal{L}$ is a line bundle on $X$ and $s_0,\dotsc,s_N\in \Gamma(X,\mathcal{L})$ are global sections generating $\mathcal{L}$, then there exists a unique morphism of \textcolor{red}{what?} $\varphi:X\lra \mathbb{P}^N$ such that $\mathcal{L}\cong \varphi^*(\mathcal{O}(1))$ and $s_j=\varphi^*(x_j)$ for each $j=0,\dotsc,N$ under this isomorphism. %\end{unteraufgaben} \item \input{q_2.tex} %\input a_2.tex %\pagebreak %\item %Let $n\in\ZZ_{>0}$. %\begin{enumerate}[(a)] %\item Check that $||z||=\sqrt{\sum_{j=0}^n z_j\bar{z}_j}$ defines a real, type (1,1) differential $2$-form on $\PP^n$, the Fubini-Study form $\omega_{\text{FS}}$. %\item Prove that %\begin{align*} %\omega_{\text{FS}}=\frac{i}{2\pi}\partial\bar{\partial}\log||z||^2. %\end{align*} %\item Prove that the differential form %\begin{align*} %\gamma=\frac{i}{2\pi}\frac{||z||^2\left(\sum_{j=0}^n dz_j\wedge d\bar{z}_j\right)-\left(\sum_{j=0}^n \bar{z}_j dz_j\right)\wedge \left(\sum_{k=0}^n z_k d\bar{z}_k\right)}{||z||^4} %\end{align*} %is closed and invariant under the action of the unitary group $U(n+1)$. %\end{enumerate} %\item \input q_3.tex %\input a_3.tex \item \input q_5.tex %\input a_4.tex %\item \input q_5.tex %\input a_5.tex3 %\item \input q_6.tex %\input a_6.tex \end{aufgaben} %\begin{aufgaben} %\addtocounter{aufgabe}{5} %\item %\end{aufgaben} \end{document}