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Schubert2 :: ctop(AbstractSheaf)

ctop(AbstractSheaf) -- the top Chern class of an abstract sheaf

Synopsis

Description

Here we compute the top Chern class of a vector bundle of rank 6 on the way toward getting the number of lines on quintic threefold.

i1 : G = flagBundle{3,2}

o1 = G

o1 : a flag bundle with subquotient ranks {3, 2}
i2 : B = symmetricPower_5 last bundles G

o2 = B

o2 : an abstract sheaf of rank 6 on G
i3 : ctop B

          3
o3 = 2875H
          2,2

                                            QQ[][H   ..H   , H   ..H   ]
                                                  1,1   1,3   2,1   2,2
o3 : ---------------------------------------------------------------------------------------------------------
     (- H    - H   , - H    - H   H    - H   , - H    - H   H    - H   H   , - H   H    - H   H   , -H   H   )
         1,1    2,1     1,2    1,1 2,1    2,2     1,3    1,2 2,1    1,1 2,2     1,3 2,1    1,2 2,2    1,3 2,2
i4 : degree oo

o4 = {6}

o4 : List
i5 : integral ooo

o5 = 2875