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D.15.3.13 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)
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