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D.5.2.13 ChernRootsSum

Procedure from library chern.lib (see chern_lib).

Usage:
ChernRootsSum(a, b); a, b lists of polynomials

Return:
list of polynomials

Purpose:
computes the Chern roots of the direct (Whitney) sum of a vector bundle with Chern roots a and a vector bundle with Chern roots b

Note:

Example:
 
LIB "chern.lib";
ring r = 0, (a(1..3), b(1..2)), dp;
// assume a(1), a(2), a(3) are the Chern roots of a vector bundle E
// assume b(1), b(2) are the Chern roots of a vector bundle F
list l=a(1..3);
list L=b(1..2);
// the Chern roots of their direct sum is
print( ChernRootsSum(l, L) );
==> [1]:
==>    a(1)
==> [2]:
==>    a(2)
==> [3]:
==>    a(3)
==> [4]:
==>    b(1)
==> [5]:
==>    b(2)