\magnification=1200
\hsize=4in
\overfullrule=0pt
\input amssym
%\def\frac#1 #2 {{#1\over #2}}
\def\emph#1{{\it #1}}
\def\em{\it}
\nopagenumbers
\noindent
%
%
{\bf Anisse Kasraoui and Jiang Zeng}
%
%
\medskip
\noindent
%
%
{\bf Distribution of Crossings, Nestings and Alignments of Two Edges in Matchings and Partitions}
%
%
\vskip 5mm
\noindent
%
%
%
%
We construct an involution on set partitions which keeps track of the
numbers of crossings, nestings and alignments of two edges. We derive
then the symmetric distribution of the numbers of crossings and
nestings in partitions, which generalizes a recent result of Klazar
and Noy in perfect matchings. By factorizing our involution through
bijections between set partitions and some path diagrams we obtain the
continued fraction expansions of the corresponding ordinary generating
functions.
\bye