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User: Tim Graefnitz

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A353195 Coefficients of the open mirror map of P2.

Original entry on oeis.org

2, 5, 32, 286, 3038, 35870, 454880, 6073311, 84302270, 1206291308, 17687468032, 264593385735, 4024945917314, 62101640836955, 969921269646560, 15309505269479942, 243897741785306000, 3917478255634975373, 63381933612745811168, 1032176017566352265886, 16907912684907490828614
Offset: 1

Author

Tim Graefnitz, Apr 29 2022

Keywords

Comments

The integers a[k] (k>0) defining this sequence are the coefficients of the open mirror map M(Q)=sum(k>0)a[k]Q^k, which is defined as follows:
Let F(z) = Sum_(k>0)((-1)^k*(3k)!/(k*(k!)^3)*z^k) be the holomorphic part of the logarithmic solution to the Picard-Fuchs type differential equation for P2 as defined by Lerche-Mayr (cf. A006480).
The inverse of the power series Q(z)=z*exp(F(z)) is defined as the closed mirror map z(Q) (c.f. A229451 and A061401).
The holomorphic part of the logarithmic solution to the open Picard-Fuchs equation for P2 is given by (1/3)*F(z).
The open mirror map M(Q) is obtained by inserting the closed mirror map z(Q) into the power series exp(1/3*F(z)).
The series M(Q) originally appeared as the open mirror map relating Aganagic-Vafa branes on the canonical bundle of P2 ("local P2") and its mirror.
The coefficients of the series M(Q) can be interpreted as curve counts in different ways:
(1) a[d] is the open Gromov-Witten invariant (counts of holomorphic disks) of moment fibers of local P2, of class d*H (H = hyperplane class) and winding w=1.
(2) a[d] is the closed local Gromov-Witten invariant of local F1 (F1 = Hirzebruch surface = blowup of P2) of class d*H-C (H = pullback of hyperplane class, C = exceptional line).
(3) a[d] is the relative (or log) Gromov-Witten invariant of the pair (F1,D) (D = smooth anticanonical divisor) of class d*H-C.
(4) a[d] is the 2-marked log Gromov-Witten invariant R_p,q of the pair (P2,D) (D = smooth anticanonical divisor) of class d*H, intersecting D in two points with multiplicity p and q, the former point is fixed.
(5) W = y + Sum_(d>0) a[d]*t^(3d)*y^(-3d+1) is the proper Landau-Ginzburg model of (P2,D) defined via broken lines.
There is no known recursion or closed formula for this sequence.
Conjecture: a(n) = (3*n - 1)*A364973(n). - - Kyler Siegel, Jul 06 2024

Crossrefs

Programs

  • SageMath
    def M(n):
        z,Q = var('z,Q')
        a = [var(f'a{k}') for k in range(n+1)]
        b = [0,1] + [0 for k in range(2,n+1)]
        F = sum([(-1)^k/k*factorial(3*k)/factorial(k)^3*z^k for k in range(1,n+1)])
        zQ = Q+sum([a[k]*Q^k for k in range(2,n+1)])
        Qz = (zQ*exp(F(zQ))).taylor(Q,0,n)
        for k in range(2,n+1):
            b[k] = a[k].substitute(solve(Qz.coefficient(Q^k).substitute([a[i]==b[i] for i in range(k)]) == 0,a[k]))
        return exp(1/3*F).substitute(z==sum([b[k]*Q^k for k in range(n+1)])).taylor(Q,0,n)