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Riemann-Hilbert-Birkhoff inverse problem for semisimple flat $F$-manifolds, and convergence of oriented associativity potentials

Giordano Cotti

Abstract

In this paper, we address the problem of classification of quasi-homogeneous formal power series providing solutions of the oriented associativity equations. Such a classification is performed by introducing a system of monodromy local moduli on the space of formal germs of homogeneous semisimple flat $F$-manifolds. This system of local moduli is well-defined on the complement of the "strictly doubly resonant" locus, namely a locus of formal germs of flat $F$-manifolds manifesting both coalescences of canonical coordinates at the origin, and resonances of their "conformal dimensions". It is shown how the solutions of the oriented associativity equations can be reconstructed from the knowledge of the monodromy local moduli via a Riemann-Hilbert-Birkhoff boundary value problem. Furthermore, standing on results of B.Malgrange and C.Sabbah, it is proved that any formal homogeneous semisimple flat $F$-manifold, which is not strictly doubly resonant, is actually convergent. Our semisimplicity criterion for convergence is also reformulated in terms of solutions of Losev-Manin commutativity equations, growth estimates of correlators of $F$-cohomological field theories, and solutions of open Witten-Dijkgraaf-Verlinde-Verlinde equations.

Riemann-Hilbert-Birkhoff inverse problem for semisimple flat $F$-manifolds, and convergence of oriented associativity potentials

Abstract

In this paper, we address the problem of classification of quasi-homogeneous formal power series providing solutions of the oriented associativity equations. Such a classification is performed by introducing a system of monodromy local moduli on the space of formal germs of homogeneous semisimple flat -manifolds. This system of local moduli is well-defined on the complement of the "strictly doubly resonant" locus, namely a locus of formal germs of flat -manifolds manifesting both coalescences of canonical coordinates at the origin, and resonances of their "conformal dimensions". It is shown how the solutions of the oriented associativity equations can be reconstructed from the knowledge of the monodromy local moduli via a Riemann-Hilbert-Birkhoff boundary value problem. Furthermore, standing on results of B.Malgrange and C.Sabbah, it is proved that any formal homogeneous semisimple flat -manifold, which is not strictly doubly resonant, is actually convergent. Our semisimplicity criterion for convergence is also reformulated in terms of solutions of Losev-Manin commutativity equations, growth estimates of correlators of -cohomological field theories, and solutions of open Witten-Dijkgraaf-Verlinde-Verlinde equations.

Paper Structure

This paper contains 40 sections, 74 theorems, 265 equations, 6 figures.

Key Result

Theorem 1.2

Any homogeneous semisimple (analytic/formal) pointed germ of flat $F$-manifold, which is not strictly doubly resonant, is uniquely determined by its monodromy data. In particular, the vector potential $\bm F$ can be explicitly reconstructed from the monodromy data via a Riemann-Hilbert-Birkhoff boun

Figures (6)

  • Figure 1: Contour $\Gamma$, paths $\Gamma_{\pm\infty},\Gamma_1,\Gamma_2$, domains $\Pi_0,\Pi_L,\Pi_R$, and $\pm$ sides of $\Gamma$.
  • Figure 2: A stable 12-pointed chain of projective lines.
  • Figure 3: Isomorphism classes of one edges $n$-trees are parametrized by stable unordered 2-partition s $\sigma=\{S_1,S_2\}$ of $\{1,\dots,n\}$.
  • Figure 4:
  • Figure 5: Two stable $8$-trees $\tau_1$ and $\tau_2$.
  • ...and 1 more figures

Theorems & Definitions (130)

  • Remark 1.1
  • Theorem 1.2: Cf. Theorems \ref{['enF']}, \ref{['mthm1']}
  • Theorem 1.3: Cf. Theorem \ref{['thconv']}
  • Definition 2.1
  • Lemma 2.2
  • Definition 2.3
  • Remark 2.4
  • Remark 2.5
  • Definition 2.6
  • Remark 2.7
  • ...and 120 more