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D.15.3.31 chWedge
Procedure from library chern.lib (see chern_lib).
- Usage:
- chWedge(k, r, c [,pos]); k, r integers, c list of polynomials, pos list of integers
- Return:
- list with entries: int N, list of polynomials l
- Purpose:
- computes the rank and the Chern classes of the exterior power of a vector bundle
- Note:
- for the second exterior power chWedge2L(...) could be faster
Example:
| | LIB "chern.lib";
ring r=0, (c(1..5)), dp;
list l=c(1..5);
// the rank and the Chern classes of the second exterior power of a vector bundle of rank 3
print( chWedge(2, 3, l) );
==> [1]:
==> 3
==> [2]:
==> [1]:
==> 2*c(1)
==> [2]:
==> c(1)^2+c(2)
==> [3]:
==> c(1)*c(2)-c(3)
// the rank and the first 3 Chern classes
// of the fourth exterior power of a vector bundle of rank 5
print( chWedge(4, 5, l, 1, 2, 3) );
==> [1]:
==> 5
==> [2]:
==> [1]:
==> 4*c(1)
==> [2]:
==> 6*c(1)^2+c(2)
==> [3]:
==> 4*c(1)^3+3*c(1)*c(2)-c(3)
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