%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 7-5-5 on page 510.
%% 
%%  Copyright (C) 2007 Michel Goossens, Frank Mittelbach, Denis Roegel, Sebastian Rahtz, Herbert Vo\ss 
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 

\documentclass{ttctexa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{348.0pt}
\StartShownPreambleCommands
\usepackage[all,arc,knot]{xy}
\StopShownPreambleCommands
\begin{document}
\[
\xy (-15,0)*{};(15,0)*{}; (-8,10)*{}="TL";
(0,10)*{}="TR"; (-8,-10)*{}="BL"; (0,-10)*{}="BR"; (8,10)*{}="RU";
(8,-10)*{}="RB";
"TL";"BL" **\dir{-};
?(.5)*\dir{<};
"TR";"BR" **\dir{-};
?(.5)*\dir{>};
"TL";"TR" **\crv{(-8,18)& (0,18)};
"BL";"BR" **\crv{(-8,-18)& (0,-18)};
"RU";"TR" **\crv{~*=<2pt>{.}(8,4)& (0,4)};
"RB";"BR" **\crv{~*=<2pt>{.}(8,-4)& (0,-4)};
(8,0)*{\scriptstyle F_{-1}}; (8,0)*\xycircle(2.75,2.75){-}="f";
(8,14)**\dir{-} ?(.75)*\dir{>}+(5,-1)*{\scriptstyle
\overline{F(x)}}; "f";(8,-14)**\dir{-}
?(.5)*\dir{<}+(5,-1)*{\scriptstyle F(\bar{x})};
(-12,5)*{\scriptstyle \overline{F(x)}};
\endxy
\]
\end{document}
