4.8.3 map operations
--------------------


( )
composition of maps. If, for example, f and g are maps,
then f(g) is a map expression giving the composition of f
and g.

map_expression [ int_expressions ]
is a map entry (the image of the corresponding variable)


Example:
  ring r=0,(x,y),dp;
  map f=r,y,x;    // the map f permutes the variables
  f;
==> f[1]=y
==> f[2]=x
  poly p=x+2y3;
  f(p);
==> 2x3+y
  map g=f(f);    // the map g defined as  f^2 is the identity
  g;
==> g[1]=x
==> g[2]=y
  g(p) == p;
==> 1

<font size="-1">
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; User manual for <a href="http://www.singular.uni-kl.de/"><i>Singular</i></a> version 2-0-4, October 2002,
generated by <a href="http://www.gnu.org/software/texinfo/"><i>texi2html</i></a>.
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