Home Online Manual
Top
Back: powSumSym
Forward: chAllInv
FastBack:
FastForward:
Up: chern_lib
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document

D.15.2.10 chAll

Procedure from library chern.lib (see chern_lib).

Usage:
chAll(l [,N]); l a list of polynomials, N integer

Return:
list of polynomials

Purpose:
computes the list of terms of positive degree [up to degree N] of the Chern character, where the entries of l are considered as the Chern classes

Note:
makes sense only for a list of polynomials

Example:
 
LIB "chern.lib";
// Chern character (terms of degree 1, 2, 3)
// corresponding to the Chern classes c(1), c(2), c(3):
ring r = 0, (c(1..3)), dp;
list l=(c(1..3));
print(chAll(l));
==> [1]:
==>    c(1)
==> [2]:
==>    1/2*c(1)^2-c(2)
==> [3]:
==>    1/6*c(1)^3-1/2*c(1)*c(2)+1/2*c(3)
// terms up to degree 5 in the same situation
print(chAll(l, 5));
==> [1]:
==>    c(1)
==> [2]:
==>    1/2*c(1)^2-c(2)
==> [3]:
==>    1/6*c(1)^3-1/2*c(1)*c(2)+1/2*c(3)
==> [4]:
==>    1/24*c(1)^4-1/6*c(1)^2*c(2)+1/12*c(2)^2+1/6*c(1)*c(3)
==> [5]:
==>    1/120*c(1)^5-1/24*c(1)^3*c(2)+1/24*c(1)*c(2)^2+1/24*c(1)^2*c(3)-1/24*c\
   (2)*c(3)