Double $J$-function of stable quasimap invariants for complete intersection in Grassmannian
Mu-Lin Li

TL;DR
This paper derives explicit formulas for the $J$-function and double $J$-function of stable quasimaps to complete intersections in Grassmannians using localization techniques.
Contribution
It provides new explicit formulas for $J$-functions and double $J$-functions in the context of stable quasimaps to Grassmannians, advancing computational methods in enumerative geometry.
Findings
Explicit formulas for $J$-function of stable quasimaps.
Explicit formulas for double $J$-function of stable quasimaps.
Application of localization methods to Grassmannian quasimaps.
Abstract
Using localization methods on the moduli space of stable quasimaps to Grassmannian, we give explicit formulas of -function and double -function of stable quasimaps for complete intersection in Grassmannian.
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Taxonomy
TopicsAlgebraic Geometry and Number Theory · Geometric and Algebraic Topology · Advanced Combinatorial Mathematics
Double -function of stable quasimap invariants for complete intersection in Grassmannian
Mu-lin Li
College of Mathematics and Econometrics, Hunan University, China
Abstract.
Using localization methods on the moduli space of stable quasimaps to Grassmannian, we give explicit formulas of -function and double -function of stable quasimaps for complete intersection in Grassmannian.
1. introduction
The moduli space of stable quotients was first constructed and studied by Marian, Oprea and Pandharipande [7]. Cooper and Zinger [5] calculated the -function of stable quotients for projective complete intersections, and proved that it is related to the genus zero Gromov-Witten invariants by mirror map. Later Zinger [10] calculated the double and the triple -functions of stable quotients for projective complete intersections. Ciocan-Fontanine, Kim and Maulik [4] generalized the definition of stable quotients to arbitrary GIT quotients by the notion of stable quasimaps. Ciocan-Fontanine and Kim proved that the genus zero stable quasimap invariants (including twisted cases) are related to stable map by mirror map in [2], and for the higher genus cases of projective complete intersections in [3]. In this paper, using the abelian non-abelian relation between Grassamannian and product of projective spaces as in [1], we analyze the -function and the double -function of stable quasimaps for complete intersection in Grassmannian cases, which should play a key role in the computation of the genus one stable quasimap invariants for complete intersection in Grassmannian.
Let be the space of all -dimensional subspaces of . Recall that the cohomology of has the presentation:
[TABLE]
where are the elementary symmetric polynomials of two variables (the Chern roots of the dual universal bundle), and is the -th complete symmetric polynomial (sums of all monomials of degree ) of . Denote by . Let be a basis of such that the Poincaré dual of the diagonal class can be written as
[TABLE]
where is a symmetry polynomial of degree in .
Denote by the moduli of genus zero and degree stable quasimaps to with two marked points. Let
[TABLE]
be the evaluation map at the -th marked point, see [2]. For each , let be the first Chern class of the universal cotangent line bundle for the -th marked point. Let
[TABLE]
be the universal family, and be the sections given by the marked points. Let
[TABLE]
be the universal bundle. Let .
For and -tuple of positive integers, denote
[TABLE]
Let
[TABLE]
[TABLE]
and
[TABLE]
In particular, , and are locally free sheaves. The -functions associated to stable quotients are defined as
[TABLE]
[TABLE]
The double -function is defined as
[TABLE]
[TABLE]
Let
[TABLE]
Let
[TABLE]
where
[TABLE]
Denote by
[TABLE]
. Let , be defined as in Section 4.
Theorem 1.1**.**
If , , and are such that , then
[TABLE]
and
[TABLE]
Theorem 1.2**.**
If , , and are such that , then
[TABLE]
and
[TABLE]
where
[TABLE]
[TABLE]
Theorem 1.3**.**
If , , and are such that , then
[TABLE]
Acknowledgment: The author thanks Wanmin Liu for helpful discussions. This work was supported by Start-up Fund of Hunan University.
2. Equivariant cohomology
Let be the space of all -dimensional subspaces of . It has a torus action induced by the standard torus action on . The fixed points of are the 2-planes spanned by , where is the standard basis of . We label by . Let be the set of all the pairs with . Thus with is the collection of all the fixed points.
Denote by , where . Here
[TABLE]
are the projection onto the -th component and the tautological line bundle respectively. Denote by . Let be the fractional field of .
Let be the equivariant Chern root of the dual universal bundle, who’s non-equivariant counterpart are . Let , then
[TABLE]
where and are factorial elementary and complete symmetric functions which symmetric in , see [8, Proposition 5.2].
Let
[TABLE]
Then is the equivariant Poincaré dual of the points . The Artiyah-Bott localization theorem states that
[TABLE]
Therefore
[TABLE]
So for
[TABLE]
Let be the universal bundle. Thus, the action of on naturally lifts to an action on and the Euler class
[TABLE]
The -action on also has a natural lift to the tangent bundle so that there is a short exact sequence
[TABLE]
Therefore
[TABLE]
3. Algebraic calculation
In this section we describe a number of properties of hypergeometric series which determine them uniquely.
If is a ring, denote by
[TABLE]
the -algebra of Laurent series in (with finite principal part). For and , let be the coefficient of in . If
[TABLE]
for some , we define
[TABLE]
i.e. we drop and higher powers of , instead of higher powers of . If is a field, let
[TABLE]
be the embedding given by taking the Laurent series of rational functions at .
If is a rational function in and possibly with some other variables, then for any , denote the residue of the 1-form at by
[TABLE]
where the integral is taken over a positively oriented loop around with no other singular points of . For any collection of points , let
[TABLE]
By the Residue Theorem on ,
[TABLE]
for every rational function on . If is regular at , let \left\llbracket f\right\rrbracket_{z;p} be the coefficient of in the power series expansion of around .
Definition 3.1**.**
Let be any collection of elements of , with . A symmetric power series is -recursive if the following holds: if is such that
[TABLE]
and \big{\llbracket}{{\cal F}(\alpha_{i},\alpha_{j},\hbar,q)}\big{\rrbracket}_{q;d} is regular at and for all , and , then
[TABLE]
Thus, if is -recursive, for any collection , then
[TABLE]
as can be seen by induction on . Moreover,
[TABLE]
for some . The nominal issue with defining -recursivity by (3), as is normally done, is that a priori the evaluation of at and need not be well-defined, since is a power series in with coefficients in the Laurent series in ; a priori they may not converge anywhere. However, taking the coefficient of each power of in (3) shows by induction on the degree that this evaluation does make sense. This is the substance of Definition 3.1.
Definition 3.2**.**
Let be a homogeneous polynomial such that taking value at , is well-defined and nonzero for every . For any , and symmetric on , define
[TABLE]
which is in . The pair satisfies -mutual polynomiality condition (-MPC) if . If , we call that satisfies -self polynomiality condition (-SPC).
Proposition 3.3** ([10, Proposition 6.3]).**
Let . If and are -recursive, for some collection of elements of , and satisfies -MPC, with
[TABLE]
for all , then if and only if .
Proposition 3.4**.**
Let
[TABLE]
and
[TABLE]
where , are polynomials in symmetric on , and , are the product of \bigg{(}\prod_{i=1}^{n}(\mathbf{x}_{1}-\alpha_{i}+l\hbar)-\prod_{i=1}^{n}(\mathbf{x}_{1}-\alpha_{i})\bigg{)} and \bigg{(}\prod_{i=1}^{n}(\mathbf{x}_{2}-\alpha_{i}+l\hbar)-\prod_{i=1}^{n}(\mathbf{x}_{2}-\alpha_{i})\bigg{)} with , . Let be defined as in Definition 3.2, then
[TABLE]
Proof.
Denote by
[TABLE]
Since and are not zero when for all ,
[TABLE]
Thus, by the Residue Theorem on ,
[TABLE]
Since and are not zero when ,
[TABLE]
Therefore
[TABLE]
On the other hand
[TABLE]
where is a product of \bigg{(}\prod_{i=1}^{n}(\mathbf{x}_{1}-\alpha_{i}+l\hbar)-\prod_{i=1}^{n}(\mathbf{x}_{1}-\alpha_{i})\bigg{)}, which is not zero when . Thus , and the -summand of is times an element of \mathbb{Q}_{\alpha}[\hbar]\left\llbracket z\right\rrbracket. Therefore
[TABLE]
∎
3.1. Recursive
Definition 3.5**.**
Let be any collection of elements of , with , where is the collection of the pairs with . A power series is -recursive if the following holds:
[TABLE]
with .
For which is symmetry on , Let
[TABLE]
Proposition 3.6**.**
If is a symmetry function on and -recursive as in Definition 3.5, then is -recursive as in Definition 3.1 with
[TABLE]
Proof.
is -recursive, thus
[TABLE]
[TABLE]
Therefore
[TABLE]
So
[TABLE]
[TABLE]
By the Residue Theorem on ,
[TABLE]
So is -recursive with relations as (3.7). ∎
Denote by . Let as
[TABLE]
with . Let
[TABLE]
Note that can be considered as the associated -functions of . By [10, Section 6, Page 477], we have the following result.
Lemma 3.7**.**
If , the power series are and -recursive respectively.
Therefore
[TABLE]
similarly for .
For all , denote
[TABLE]
Under the conditions
[TABLE]
and can be written as
[TABLE]
[TABLE]
just changing to , to , to .
Therefore and satisfy the -recursive as defined in Definition 3.5.
Denote
[TABLE]
and
[TABLE]
Thus are the non-equivariant form of
[TABLE]
Let
[TABLE]
[TABLE]
By Proposition 3.6 and Proposition 3.4, we have
Corollary 3.8**.**
The power series , , are -recursive as in (3.1) with and given as above. Moreover, satisfies -SPC with , and satisfies -MPC.
3.2. Differential operators on hypergeometric functions
Denote , and . Fix an element . For , . Denote
[TABLE]
for some homogeneous polynomials satisfying
[TABLE]
By [9, Section 4], there exists differential operators , where , such that in satisfies the following properties:
- There exist with , , such that \left\llbracket{\cal C}^{(\mathbf{r})}_{\mathbf{p},s}\right\rrbracket_{\mathbf{q};{\mathbf{d}}} is a homogeneous polynomial in of degree ,
[TABLE]
[TABLE]
and
[TABLE]
Let be a polynomial of operator such that
[TABLE]
Denote by
[TABLE]
[TABLE]
Define
[TABLE]
where is the set of all the symmetric polynomials of with degree . Then
[TABLE]
In particular as an element of is invertible, with given by
[TABLE]
We define
[TABLE]
Then
[TABLE]
and
[TABLE]
Define for and with and by
[TABLE]
These equations indeed uniquely determine , since
[TABLE]
Induction by (3.18) and (3.2), we obtain
[TABLE]
Similarly we can define for .
Proposition 3.9**.**
The power series and are -recursive as in (3.1) with and as (3.10) and (3.11). Moreover, satisfies -MPC with , and satisfies -MPC.
Proof.
By [9, Lemma 5.8 (a)], and are -recursive. Then by Proposition 3.6 and [9, Lemma 5.8(b)], and are -recursive as in Definition 3.1.
The second assertion follows from Proposition 3.4. ∎
4. localization formula
The standard -action on (as well as any other representation) induces corresponding -actions on , , , , and . Thus, , , and have well-defined equivariant Euler classes
[TABLE]
The universal cotangent line bundle for the -th marked point also has a well-defined equivariant Euler class, which will still be denoted by . Let
[TABLE]
[TABLE]
where is as before.
Let be the equivariant class of the diagonal
[TABLE]
where are homogeneous polynomials.
Let
[TABLE]
where .
Let
[TABLE]
Let
[TABLE]
where .
Marian, Oprea and Pandharipande [7, Section 7.3] described the fixed loci of the -action on , which are indexed by connected decorated graphs. However, in the case , the relevant graphs consist of a single strand (possibly consisting of a single vertex) with the two marked points attached at the opposite ends of the strand. Such a graph can be described by an ordered set of vertices, where is a strict order on the finite set . Given such a strand, denote by and its minimal and maximal elements and by Edg its set of edges, i.e. of pairs of consecutive elements. A decorated strand is a tuple
[TABLE]
where is a strand as above and
[TABLE]
are maps such that
[TABLE]
In Figure 1, the vertices of a decorated strand are indicated by dots in the increasing order, with respect to , from left to right. Let be the fixed locus of corresponding to a decorated strand , then isomorphic to
[TABLE]
up to a finite quotient, where is the Hassett moduli space of weighted pointed stable curves. Let be the restriction of universal family . The universal bundle is split when restricting on . We denote by .
Lemma 4.1**.**
* are -recursive. Moreover, satisfies -SPC, and satisfy -MPC with . are -recursive, and , satisfy -MPC.*
Proof.
The recursive of and can be proved parallel to [10, Lemma 6.5], or be obtained by just applying [3, Lemma 7.5.2] to the twisted case of , and be considered as GIT qoutient .
The proofs of polynomiality are parallel to [10, Lemma 6.6]. We sketch it as follows.
Denote by the standard action on by . Let be the representation of with weight [math], and . For , the action on induced an action on
[TABLE]
Let
[TABLE]
be the equivariant hyperplane class. Let
[TABLE]
Using Plücker embedding, we have the following morphism
[TABLE]
Then applying localization formula we can prove
[TABLE]
with , and
[TABLE]
which are in . ∎
Denote by
[TABLE]
.
Theorem 4.2**.**
If , , and are such that , then
[TABLE]
and
[TABLE]
Proof.
The proof is parallel to [5, Theorem 3].
When ,
[TABLE]
For ,
[TABLE]
Thus
[TABLE]
Therefore
[TABLE]
When . By Lemma 4.1, is -recursive, therefore
[TABLE]
for some .
Parallel to the proof of [5, Proposition 6.1], by applying localization formula to , for all , we have
[TABLE]
Parallel to the proof of [5, Proposition 8.3], we have
[TABLE]
This means that and satisfy the same recursive relations. For their coefficients of are the same,
[TABLE]
[TABLE]
Then by [6, Lemma 30.3.2],
[TABLE]
Because satisfy 1-MPC, satisfy 1-MPC. For satisfy 1-MPC, and
[TABLE]
By Proposition 3.3, we have
[TABLE]
∎
Theorem 4.3**.**
If , , and are such that , then
[TABLE]
where
[TABLE]
and are defined as in (3.19).
Proof.
By the definition of ,
[TABLE]
By Proposition 3.3 and Lemma 4.1,
[TABLE]
Similar argument holds for and . ∎
Theorem 4.4**.**
If , , and are such that , then
[TABLE]
Proof.
[TABLE]
for all . By Lemma 4.1, the coefficient of in is -recursive and satisfies -MPC with respect to for all . By Proposition 3.3, it follows that in order to prove (4.14) it suffices to show that
[TABLE]
The right-hand side of (4.16) mod is
[TABLE]
The left-hand side of (4.16) mod is
[TABLE]
By Lemma 4.1, (4.18) is -recursive and satisfies -MPC with respect to . Since (4.17) also satisfies these properties. The power series (4.18) and (4.17) agree if only if they agree mod . The latter is the case since both are the equivariant Poincaré dual to the diagonal restricted to . ∎
Denote by
[TABLE]
[TABLE]
By restricting on , Theorem 4.2, Theorem 4.3 and Theorem 4.4 give us the non-equivariant Theorem 1.1, Theorem 1.2 and Theorem 1.3.
The reference list from the paper itself. Each links out to its DOI / PubMed record.
- 1[1] A. Bertram, I. Ciocan-Fontanine, and B. Kim, Two proofs of a conjecture of Hori and Vafa , Duke Math. J. 126 (2005), no. 1, 101-136.
- 2[2] I. Ciocan-Fontanine and B. Kim, Wall-crossing in genus zero quasimap theory and mirror maps , Algebraic Geometry, 4 (2014), 400-448.
- 3[3] I. Ciocan-Fontanine and B. Kim, Higher genus quasimap wall-crossing for semi-positive targets , to appear in JEMS.
- 4[4] I. Ciocan-Fontanine, B. Kim and D. Maulik, Stable quasimaps to GIT quotients , J. of Geometry and Physics, 75 (2014), 17-47.
- 5[5] Y. Cooper and A. Zinger, Mirror symmetry for stable quotients invariants , Michigan Math. J., 63 (2014), no. 3, 571-621.
- 6[6] K. Hori, S. Katz, A. Klemm, R. Pandharipande, R. Thomas, C. Vafa, R. Vakil, and E. Zaslow, Mirror Symmetry , Clay Math. Monographs 1, Amer. Math. Soc., Providence, RI, 2003.
- 7[7] A. Marian, D. Oprea and R. Pandharipande, The moduli space of stable quotients , Geom. Topol. 15 (2011), no. 3, 1651-1706.
- 8[8] C. Leonardo Constantin Mihalcea, Giambelli formulae for the equivariant quantum cohomology of the Grassmannian , Trans. Amer. Math. Soc., 360(5):2285–2301, 2008.
