\documentclass[12pt,titlepage]{article} \usepackage{amsmath} \usepackage{mathrsfs} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsthm} \usepackage{mathtools} \usepackage{graphicx} \usepackage{color} \usepackage{ucs} \usepackage[utf8x]{inputenc} \usepackage{xparse} \usepackage{hyperref} %----Macros---------- % % Unresolved issues: % % \righttoleftarrow % \lefttorightarrow % % \color{} with HTML colorspec % \bgcolor % \array with options (without options, it's equivalent to the matrix environment) % Of the standard HTML named colors, white, black, red, green, blue and yellow % are predefined in the color package. Here are the rest. \definecolor{aqua}{rgb}{0, 1.0, 1.0} \definecolor{fuschia}{rgb}{1.0, 0, 1.0} \definecolor{gray}{rgb}{0.502, 0.502, 0.502} \definecolor{lime}{rgb}{0, 1.0, 0} \definecolor{maroon}{rgb}{0.502, 0, 0} \definecolor{navy}{rgb}{0, 0, 0.502} \definecolor{olive}{rgb}{0.502, 0.502, 0} \definecolor{purple}{rgb}{0.502, 0, 0.502} \definecolor{silver}{rgb}{0.753, 0.753, 0.753} \definecolor{teal}{rgb}{0, 0.502, 0.502} % Because of conflicts, \space and \mathop are converted to % \itexspace and \operatorname during preprocessing. % itex: \space{ht}{dp}{wd} % % Height and baseline depth measurements are in units of tenths of an ex while % the width is measured in tenths of an em. \makeatletter \newdimen\itex@wd% \newdimen\itex@dp% \newdimen\itex@thd% \def\itexspace#1#2#3{\itex@wd=#3em% \itex@wd=0.1\itex@wd% \itex@dp=#2ex% \itex@dp=0.1\itex@dp% \itex@thd=#1ex% \itex@thd=0.1\itex@thd% \advance\itex@thd\the\itex@dp% \makebox[\the\itex@wd]{\rule[-\the\itex@dp]{0cm}{\the\itex@thd}}} \makeatother % \tensor and \multiscript \makeatletter \newif\if@sup \newtoks\@sups \def\append@sup#1{\edef\act{\noexpand\@sups={\the\@sups #1}}\act}% \def\reset@sup{\@supfalse\@sups={}}% \def\mk@scripts#1#2{\if #2/ \if@sup ^{\the\@sups}\fi \else% \ifx #1_ \if@sup ^{\the\@sups}\reset@sup \fi {}_{#2}% \else \append@sup#2 \@suptrue \fi% \expandafter\mk@scripts\fi} \def\tensor#1#2{\reset@sup#1\mk@scripts#2_/} \def\multiscripts#1#2#3{\reset@sup{}\mk@scripts#1_/#2% \reset@sup\mk@scripts#3_/} \makeatother % \slash \makeatletter \newbox\slashbox \setbox\slashbox=\hbox{$/$} \def\itex@pslash#1{\setbox\@tempboxa=\hbox{$#1$} \@tempdima=0.5\wd\slashbox \advance\@tempdima 0.5\wd\@tempboxa \copy\slashbox \kern-\@tempdima \box\@tempboxa} \def\slash{\protect\itex@pslash} \makeatother % math-mode versions of \rlap, etc % from Alexander Perlis, "A complement to \smash, \llap, and lap" % http://math.arizona.edu/~aprl/publications/mathclap/ \def\clap#1{\hbox to 0pt{\hss#1\hss}} \def\mathllap{\mathpalette\mathllapinternal} \def\mathrlap{\mathpalette\mathrlapinternal} \def\mathclap{\mathpalette\mathclapinternal} \def\mathllapinternal#1#2{\llap{$\mathsurround=0pt#1{#2}$}} \def\mathrlapinternal#1#2{\rlap{$\mathsurround=0pt#1{#2}$}} \def\mathclapinternal#1#2{\clap{$\mathsurround=0pt#1{#2}$}} % Renames \sqrt as \oldsqrt and redefine root to result in \sqrt[#1]{#2} \let\oldroot\root \def\root#1#2{\oldroot #1 \of{#2}} \renewcommand{\sqrt}[2][]{\oldroot #1 \of{#2}} % Manually declare the txfonts symbolsC font \DeclareSymbolFont{symbolsC}{U}{txsyc}{m}{n} \SetSymbolFont{symbolsC}{bold}{U}{txsyc}{bx}{n} \DeclareFontSubstitution{U}{txsyc}{m}{n} % Manually declare the stmaryrd font \DeclareSymbolFont{stmry}{U}{stmry}{m}{n} \SetSymbolFont{stmry}{bold}{U}{stmry}{b}{n} % Manually declare the MnSymbolE font \DeclareFontFamily{OMX}{MnSymbolE}{} \DeclareSymbolFont{mnomx}{OMX}{MnSymbolE}{m}{n} \SetSymbolFont{mnomx}{bold}{OMX}{MnSymbolE}{b}{n} \DeclareFontShape{OMX}{MnSymbolE}{m}{n}{ <-6> MnSymbolE5 <6-7> MnSymbolE6 <7-8> MnSymbolE7 <8-9> MnSymbolE8 <9-10> MnSymbolE9 <10-12> MnSymbolE10 <12-> MnSymbolE12}{} % Declare specific arrows from txfonts without loading the full package \makeatletter \def\re@DeclareMathSymbol#1#2#3#4{% \let#1=\undefined \DeclareMathSymbol{#1}{#2}{#3}{#4}} \re@DeclareMathSymbol{\neArrow}{\mathrel}{symbolsC}{116} \re@DeclareMathSymbol{\neArr}{\mathrel}{symbolsC}{116} \re@DeclareMathSymbol{\seArrow}{\mathrel}{symbolsC}{117} \re@DeclareMathSymbol{\seArr}{\mathrel}{symbolsC}{117} \re@DeclareMathSymbol{\nwArrow}{\mathrel}{symbolsC}{118} \re@DeclareMathSymbol{\nwArr}{\mathrel}{symbolsC}{118} \re@DeclareMathSymbol{\swArrow}{\mathrel}{symbolsC}{119} \re@DeclareMathSymbol{\swArr}{\mathrel}{symbolsC}{119} \re@DeclareMathSymbol{\nequiv}{\mathrel}{symbolsC}{46} \re@DeclareMathSymbol{\Perp}{\mathrel}{symbolsC}{121} \re@DeclareMathSymbol{\Vbar}{\mathrel}{symbolsC}{121} \re@DeclareMathSymbol{\sslash}{\mathrel}{stmry}{12} \re@DeclareMathSymbol{\bigsqcap}{\mathop}{stmry}{"64} \re@DeclareMathSymbol{\biginterleave}{\mathop}{stmry}{"6} \re@DeclareMathSymbol{\invamp}{\mathrel}{symbolsC}{77} \re@DeclareMathSymbol{\parr}{\mathrel}{symbolsC}{77} \makeatother % \llangle, \rrangle, \lmoustache and \rmoustache from MnSymbolE \makeatletter \def\Decl@Mn@Delim#1#2#3#4{% \if\relax\noexpand#1% \let#1\undefined \fi \DeclareMathDelimiter{#1}{#2}{#3}{#4}{#3}{#4}} \def\Decl@Mn@Open#1#2#3{\Decl@Mn@Delim{#1}{\mathopen}{#2}{#3}} \def\Decl@Mn@Close#1#2#3{\Decl@Mn@Delim{#1}{\mathclose}{#2}{#3}} \Decl@Mn@Open{\llangle}{mnomx}{'164} \Decl@Mn@Close{\rrangle}{mnomx}{'171} \Decl@Mn@Open{\lmoustache}{mnomx}{'245} \Decl@Mn@Close{\rmoustache}{mnomx}{'244} \makeatother % Widecheck \makeatletter \DeclareRobustCommand\widecheck[1]{{\mathpalette\@widecheck{#1}}} \def\@widecheck#1#2{% \setbox\z@\hbox{\m@th$#1#2$}% \setbox\tw@\hbox{\m@th$#1% \widehat{% \vrule\@width\z@\@height\ht\z@ \vrule\@height\z@\@width\wd\z@}$}% \dp\tw@-\ht\z@ \@tempdima\ht\z@ \advance\@tempdima2\ht\tw@ \divide\@tempdima\thr@@ \setbox\tw@\hbox{% \raise\@tempdima\hbox{\scalebox{1}[-1]{\lower\@tempdima\box \tw@}}}% {\ooalign{\box\tw@ \cr \box\z@}}} \makeatother % \mathraisebox{voffset}[height][depth]{something} \makeatletter \NewDocumentCommand\mathraisebox{moom}{% \IfNoValueTF{#2}{\def\@temp##1##2{\raisebox{#1}{$\m@th##1##2$}}}{% \IfNoValueTF{#3}{\def\@temp##1##2{\raisebox{#1}[#2]{$\m@th##1##2$}}% }{\def\@temp##1##2{\raisebox{#1}[#2][#3]{$\m@th##1##2$}}}}% \mathpalette\@temp{#4}} \makeatletter % udots (taken from yhmath) \makeatletter \def\udots{\mathinner{\mkern2mu\raise\p@\hbox{.} \mkern2mu\raise4\p@\hbox{.}\mkern1mu \raise7\p@\vbox{\kern7\p@\hbox{.}}\mkern1mu}} \makeatother %% Fix array \newcommand{\itexarray}[1]{\begin{matrix}#1\end{matrix}} %% \itexnum is a noop \newcommand{\itexnum}[1]{#1} %% Renaming existing commands \newcommand{\underoverset}[3]{\underset{#1}{\overset{#2}{#3}}} \newcommand{\widevec}{\overrightarrow} \newcommand{\darr}{\downarrow} \newcommand{\nearr}{\nearrow} \newcommand{\nwarr}{\nwarrow} \newcommand{\searr}{\searrow} \newcommand{\swarr}{\swarrow} \newcommand{\curvearrowbotright}{\curvearrowright} \newcommand{\uparr}{\uparrow} \newcommand{\downuparrow}{\updownarrow} \newcommand{\duparr}{\updownarrow} \newcommand{\updarr}{\updownarrow} \newcommand{\gt}{>} \newcommand{\lt}{<} \newcommand{\map}{\mapsto} \newcommand{\embedsin}{\hookrightarrow} \newcommand{\Alpha}{A} \newcommand{\Beta}{B} \newcommand{\Zeta}{Z} \newcommand{\Eta}{H} \newcommand{\Iota}{I} \newcommand{\Kappa}{K} \newcommand{\Mu}{M} \newcommand{\Nu}{N} \newcommand{\Rho}{P} \newcommand{\Tau}{T} \newcommand{\Upsi}{\Upsilon} \newcommand{\omicron}{o} \newcommand{\lang}{\langle} \newcommand{\rang}{\rangle} \newcommand{\Union}{\bigcup} \newcommand{\Intersection}{\bigcap} \newcommand{\Oplus}{\bigoplus} \newcommand{\Otimes}{\bigotimes} \newcommand{\Wedge}{\bigwedge} \newcommand{\Vee}{\bigvee} \newcommand{\coproduct}{\coprod} \newcommand{\product}{\prod} \newcommand{\closure}{\overline} \newcommand{\integral}{\int} \newcommand{\doubleintegral}{\iint} \newcommand{\tripleintegral}{\iiint} \newcommand{\quadrupleintegral}{\iiiint} \newcommand{\conint}{\oint} \newcommand{\contourintegral}{\oint} \newcommand{\infinity}{\infty} \newcommand{\bottom}{\bot} \newcommand{\minusb}{\boxminus} \newcommand{\plusb}{\boxplus} \newcommand{\timesb}{\boxtimes} \newcommand{\intersection}{\cap} \newcommand{\union}{\cup} \newcommand{\Del}{\nabla} \newcommand{\odash}{\circleddash} \newcommand{\negspace}{\!} \newcommand{\widebar}{\overline} \newcommand{\textsize}{\normalsize} \renewcommand{\scriptsize}{\scriptstyle} \newcommand{\scriptscriptsize}{\scriptscriptstyle} \newcommand{\mathfr}{\mathfrak} \newcommand{\statusline}[2]{#2} \newcommand{\tooltip}[2]{#2} \newcommand{\toggle}[2]{#2} % Theorem Environments \theoremstyle{plain} \newtheorem{theorem}{Theorem} \newtheorem{lemma}{Lemma} \newtheorem{prop}{Proposition} \newtheorem{cor}{Corollary} \newtheorem*{utheorem}{Theorem} \newtheorem*{ulemma}{Lemma} \newtheorem*{uprop}{Proposition} \newtheorem*{ucor}{Corollary} \theoremstyle{definition} \newtheorem{defn}{Definition} \newtheorem{example}{Example} \newtheorem*{udefn}{Definition} \newtheorem*{uexample}{Example} \theoremstyle{remark} \newtheorem{remark}{Remark} \newtheorem{note}{Note} \newtheorem*{uremark}{Remark} \newtheorem*{unote}{Note} %------------------------------------------------------------------- \begin{document} %------------------------------------------------------------------- \section*{vector bundle} \hypertarget{context}{}\subsubsection*{{Context}}\label{context} \hypertarget{bundles}{}\paragraph*{{Bundles}}\label{bundles} [[!include bundles - contents]] \hypertarget{linear_algebra}{}\paragraph*{{Linear algebra}}\label{linear_algebra} [[!include homotopy - contents]] \hypertarget{vector_bundles}{}\section*{{Vector bundles}}\label{vector_bundles} \noindent\hyperlink{idea}{Idea}\dotfill \pageref*{idea} \linebreak \noindent\hyperlink{definition}{Definition}\dotfill \pageref*{definition} \linebreak \noindent\hyperlink{standard}{Standard}\dotfill \pageref*{standard} \linebreak \noindent\hyperlink{sheaftheoretic_version}{Sheaf-theoretic version}\dotfill \pageref*{sheaftheoretic_version} \linebreak \noindent\hyperlink{virtual_vector_bundles}{Virtual vector bundles}\dotfill \pageref*{virtual_vector_bundles} \linebreak \noindent\hyperlink{related_concepts}{Related concepts}\dotfill \pageref*{related_concepts} \linebreak \noindent\hyperlink{literature}{Literature}\dotfill \pageref*{literature} \linebreak \hypertarget{idea}{}\subsection*{{Idea}}\label{idea} Given some context of [[geometry]], then a \emph{vector bundle} is a collection of [[vector spaces]] that varies in a geometric way over a given base [[space]] $X$: over each [[generalized element|element]] $x \in X$ there is a [[vector space]] $V_x$, called the \emph{[[fiber]]} over $x$, and as $x$ varies in $X$, the fibers vary along in a geometric way. One also says that vector bundles are \emph{[[fiber bundles]]} whose fiber carries [[vector space]]-structure. Hence the theory of vector bundle is \emph{parameterized} [[linear algebra]]. For example \begin{itemize}% \item in [[topology]] a \emph{[[topological vector bundle]]} is a collection of [[vector spaces]] which ``vary continuously'' over a [[topological space]] $X$, \item in [[differential geometry]] a \emph{[[differentiable vector bundle]]} is a collection of vector space which ``varies differentiably'' over a [[differentiable manifold]], \item in [[algebraic geometry]] an \emph{[[algebraic vector bundle]]} is a collection of vector spaces which vary algebraically over a [[scheme]]. \end{itemize} and so on. One requires that ``locally'', on small enough patches of the base space $X$, the variation of the fibers is constant up to isomorphism (one says the vector bundle is ``locally trivial''), but the key point of vector bundles is that there may be non-trivial structure in how the collection of vector spaces ``globally glues together''. For example if $X = S^1$ is the [[circle]] regarded as a [[topological space]] in the standard way, and if we consider [[real vector spaces]], then there are up to [[isomorphism]] two different $\mathbb{R}$-vector bundles over $S^1$ whose [[fibers]] look like the 1-dimensional real vector space $\mathbb{R}$ itself, namely \begin{enumerate}% \item the [[cylinder]] \item the [[Möbius strip]]: \end{enumerate} (In these pictures each vertical interval is to be thought of as a stand-in for a copy of the [[real line]] $\mathbb{R}$.) Clearly for the cylinder nothing special happens to the fibers as one moves around the circle (one says this is a \emph{trivial vector bundle}) while the M\"o{}bius strip is ``locally trivial'' but globally has a twist: as one moves once around the circle the original fiber comes back identified with its reflection at the origin. An important class of examples of vector bundles are [[tangent bundles]] of [[differentiable manifolds]] $X$. Here the [[vector space]] at each point of $X$ is the [[tangent space]] of that point, the space of all [[tangent vectors]] based at that point. The graphics on the right shows one of the tangent space of the [[2-sphere]]. Dually, given an [[embedding of differentiable manifolds]] into a [[Euclidean space]], then the [[normal vectors]] to the tangent bundle span a vector bundle called the \emph{[[normal bundle]]} of the embedding. All the usual operations on [[finite dimensional vector spaces]] in [[linear algebra]] generalize to vector bundles by applying them [[fiber]]-wise. For instance there is [[direct sum of vector bundles]] and the [[tensor product of vector bundles]] over the same base space. To the extent that the base [[space]] $X$ is encoded in its [[algebra of functions]] (tautologically in [[algebraic geometry]] or via [[Gelfand duality]] in [[topology]]), the [[Serre-Swan theorem]] asserts that vector bundles over $X$ are equivalently encoded in the [[projective modules]] over these algebras constitutes by their [[sections]]. Vector bundles have various applications and uses: \begin{enumerate}% \item their [[Grothendieck group]] under [[direct sum of vector bundles]] yields [[topological K-theory]], an interesting [[generalized (Eilenberg-Steenrod) cohomology theory]]; \item a [[reduction of the structure group]] of vector bundles encodes actual [[geometry]] on the base space; when applied to [[tangent bundles]] such \emph{[[G-structures]]} on vector bundles encode for instance [[orthogonal structure]], [[Riemannian geometry]], [[complex geometry]], [[symplectic geometry]], [[conformal geometry]] etc. (in general: [[Cartan geometry]]); when applied to [[normal bundles]] these [[G-structures]] give rise, via [[Thom's theorem]], to [[Thom spectra]] and [[cobordism theory]]; \item equipping differentiable vector bundles with [[connection on a vector bundle]] is the basis for [[Chern-Weil theory]] and for the application of vector bundles in [[physics]], where they model [[gauge fields]] and [[instanton sectors]]; see also at \emph{[[fiber bundles in physics]]}. \end{enumerate} \hypertarget{definition}{}\subsection*{{Definition}}\label{definition} \hypertarget{standard}{}\subsubsection*{{Standard}}\label{standard} See at \emph{[[topological vector bundle]]} \hypertarget{sheaftheoretic_version}{}\subsubsection*{{Sheaf-theoretic version}}\label{sheaftheoretic_version} Vector bundles can also be defined via [[sheaf and topos theory|sheaf theory]], which permits easy transport to general [[Grothendieck toposes]]. Let $Sh(X)$ be the [[category]] of ([[set]]-valued) [[sheaf|sheaves]] on $X$. The sheaf of continuous local sections of the product projection \begin{displaymath} X \times \mathbb{R} \to X \end{displaymath} forms a [[local ring]] object $R$; when interpreted in the [[internal logic]] of $Sh(X)$, it is the Dedekind [[real numbers object]]. Then, according to a [[Serre-Swan theorem|theorem of Richard Swan]], in its sheaf-theoretic incarnation a vector bundle is the same thing as a [[projective module|projective R-module]]. \begin{itemize}% \item A theorem of Kaplansky states ``every [[projective module]] over a [[local ring]] is [[free module|free]]''. When interpreted in [[sheaf semantics]] ([[Kripke-Joyal semantics]]), the [[existential quantifier]] implicit in ``free'' is interpreted \emph{locally}, so we can consider a vector bundle as a locally free module over the Dedekind reals. \end{itemize} \hypertarget{virtual_vector_bundles}{}\subsubsection*{{Virtual vector bundles}}\label{virtual_vector_bundles} In one class of models for [[K-theory]] -- [[generalized (Eilenberg-Steenrod) cohomology]] theory -- cocycles are represented by $\mathbb{Z}_2$-graded vector bundles (pairs of vector bundles, essentially) modulo a certain equivalence relation. In that context it is sometimes useful to consider a certain variant of infinite-dimensional $\mathbb{Z}_2$-graded vector bundles called [[vectorial bundle]]s. Much else to be discussed\ldots{} \hypertarget{related_concepts}{}\subsection*{{Related concepts}}\label{related_concepts} \begin{itemize}% \item [[principal bundle]], [[associated bundle]] \item \textbf{vector bundle}, [[holomorphic vector bundle]], [[pseudoholomorphic vector bundle]] \begin{itemize}% \item [[universal vector bundle]] \item [[dual vector bundle]] \item [[module bundle]] \item [[direct sum of vector bundles]] \item [[connection on a vector bundle]] \item [[flat vector bundle]] \item [[real vector bundle]], [[complex vector bundle]] \item [[super vector bundle]] \end{itemize} \item [[2-vector bundle]] \item [[(∞,1)-vector bundle]] / [[(∞,n)-vector bundle]] \end{itemize} \hypertarget{literature}{}\subsection*{{Literature}}\label{literature} \begin{itemize}% \item Glenys Luke, Alexander S. Mishchenko, \emph{Vector bundles and their applications}, Math. and its Appl. \textbf{447}, Kluwer 1998. viii+254 pp. \href{http://www.ams.org/mathscinet-getitem?mr=99m:55019}{MR99m:55019} \item . . , \emph{ } (Russian; A. S. Mishchenko, Vector bundles and their applications) Nauka, Moscow, 1984. 208 pp. \item Howard Osborn, \emph{Vector bundles. Vol. 1. Foundations and Stiefel-Whitney classes}, Pure and Appl. Math. \textbf{101}, Academic Press 1982. xii+371 pp. \href{http://www.ams.org/mathscinet-getitem?mr=85e:55001}{MR85e:55001} \item [[Dale Husemöller]], \emph{Fibre bundles}, McGraw-Hill 1966 (300 p.); Springer GTM 1975 (327 p.), 1994 (353 p.). \item [[Dale Husemoeller]], [[Michael Joachim]], [[Branislav Jurco]], [[Martin Schottenloher]], \emph{[[Basic Bundle Theory and K-Cohomology Invariants]]}, Lecture Notes in Physics, Springer 2008 (\href{http://www.mathematik.uni-muenchen.de/~schotten/Texte/978-3-540-74955-4_Book_LNP726corr1.pdf}{pdf}) \end{itemize} An exposition with an eye towards [[gauge theory]] is in section 16.1 of \begin{itemize}% \item [[Theodore Frankel]], \emph{[[The Geometry of Physics - An Introduction]]} \item [[Raoul Bott]], [[Loring Tu]], \emph{Differential forms in algebraic topology}, Graduate Texts in Mathematics \textbf{82}, Springer 1982. xiv+331 pp. \end{itemize} Discussion with an eye towards [[K-theory]] is in \begin{itemize}% \item [[Max Karoubi]], \emph{K-theory. An introduction}, Grundlehren der Mathematischen Wissenschaften \textbf{226}, Springer 1978. xviii+308 pp. \item [[Allen Hatcher]], \emph{Vector bundles and K-Theory}, (partly finished book) \href{http://www.math.cornell.edu/~hatcher/VBKT/VBpage.html}{web} \end{itemize} [[!redirects vector bundles]] \end{document}