We present a formula for computing proper pushforwards of classes in the Chow ring of a projective bundle under the projection

$\pi :{\mathbb {P}}(\mathscr{E})\rightarrow B$
π:P(E)B⁠, for B being a non-singular compact complex algebraic variety of any dimension. Our formula readily produces generalizations of formulas derived by Sethi, Vafa, and Witten to compute the Euler characteristic of elliptically fibered Calabi-Yau fourfolds used for F-theory compactifications of string vacua. The utility of such a formula is illustrated through applications, such as the ability to compute the Chern numbers of any non-singular complete intersection in such a projective bundle in terms of the Chern class of a line bundle on B.

1.
Amrani
,
A. Al
, “
Cohomological study of weighted projective spaces
,” in
Algebraic Geometry (Ankara, 1995)
,
Lecture Notes in Pure and Applied Mathematics
Vol.
193
(
Dekker
,
New York
,
1997
), pp.
1
52
.
2.
Aluffi
,
P.
and
Esole
,
M.
, “
New orientifold weak coupling limits in F-theory
,”
J. High Energy Phys.
020
(
2
),
52
(
2010
).
3.
Denef
,
F.
, e-print arXiv:0803.1194.
4.
For the E7 case, we embed Y as a complete intersection in an unweighted
${\mathbb {P}}^{3}$
P3
bundle over B, and then apply Theorem 1.1.
5.
Fulton
,
W.
, “
Intersection theory
,”
Ergebnisse der Mathematik und ihrer Grenzgebiete (3) [Results in Mathematics and Related Areas (3)]
(
Springer-Verlag
,
Berlin
,
1984
).
6.
Here and throughout, we often write
$\mathscr{L}^a$
La
when we mean
$\pi ^{*}\mathscr{L}^a$
π*La
. The use of this elision should be clear from the context in which it is used.
7.
Here, we take the projective bundle of lines in
$\mathscr{E}$
E
.
8.
Klemm
,
A.
,
Lian
,
B.
,
Roan
,
S.-S.
, and
Yau
,
S.-T.
, “
Calabi-Yau four-folds for M- and F-theory compactifications
,”
Nuclear Phys. B
518
(
3
),
515
574
(
1998
).
9.
Sethi
,
S.
,
Vafa
,
C.
, and E.
Witten
,
E.
, “
Constraints on low-dimensional string compactifications
,”
Nuclear Phys. B
480
(
1–2
),
213
224
(
1996
).
10.
The reader not familiar with this fact may enjoy proving this using B.5.8 in Ref. 5.
11.
Vafa
,
C.
, “
Evidence for F-theory
,”
Nuclear Phys. B
469
(
3
),
403
415
(
1996
).
12.
Weigand
,
T.
, e-print arXiv:1009.3497.
You do not currently have access to this content.