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D.15.3.1 symm

Procedure from library chern.lib (see chern_lib).

Usage:
symm(l [,n]); l a list of polynomials, n integer

Return:
list of polynomials

Purpose:
computes the list of elementary symmetric functions in the entries of l

Note:
makes sense only for a list of polynomials

Example:
 
LIB "chern.lib";
// elementary symmetric functions in x, y, z:
ring r = 0, (x, y, z), dp;
list l=(x, y, z);
print(symm(l));
==> [1]:
==>    x+y+z
==> [2]:
==>    xy+xz+yz
==> [3]:
==>    xyz
//now let us compute only the first two symmetric polynomials in a(1), ... , a(10)
ring q= 0,(a(1..10)), dp;
list l=a(1..10);
print(symm(l, 2));
==> [1]:
==>    a(1)+a(2)+a(3)+a(4)+a(5)+a(6)+a(7)+a(8)+a(9)+a(10)
==> [2]:
==>    a(1)*a(2)+a(1)*a(3)+a(2)*a(3)+a(1)*a(4)+a(2)*a(4)+a(3)*a(4)+a(1)*a(5)+\
   a(2)*a(5)+a(3)*a(5)+a(4)*a(5)+a(1)*a(6)+a(2)*a(6)+a(3)*a(6)+a(4)*a(6)+a(5\
   )*a(6)+a(1)*a(7)+a(2)*a(7)+a(3)*a(7)+a(4)*a(7)+a(5)*a(7)+a(6)*a(7)+a(1)*a\
   (8)+a(2)*a(8)+a(3)*a(8)+a(4)*a(8)+a(5)*a(8)+a(6)*a(8)+a(7)*a(8)+a(1)*a(9)\
   +a(2)*a(9)+a(3)*a(9)+a(4)*a(9)+a(5)*a(9)+a(6)*a(9)+a(7)*a(9)+a(8)*a(9)+a(\
   1)*a(10)+a(2)*a(10)+a(3)*a(10)+a(4)*a(10)+a(5)*a(10)+a(6)*a(10)+a(7)*a(10\
   )+a(8)*a(10)+a(9)*a(10)