computes the list of Chern classes of the dual vector bundle
Note:
Example:
LIB "chern.lib";
// Chern classes of a vector bundle that is dual to a vector bundle
// with Chern classes c(1), c(2), c(3)
ring r=0, (c(1..3)), dp;
list l=c(1..3);
print(chDual(l));
==> [1]:
==> -c(1)
==> [2]:
==> c(2)
==> [3]:
==> -c(3)