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XZ Conjecture for G2: convex-hull criterion from vanishing torus–interval integrals

Prove that for any admissible function f: [0,1]^6 × T^8 → C, if for all positive integers P the integral ∫_{T^8} ∫_{[0,1]^5} (∫_0^{S(ξ_1)} (f(x,ξ,z))^P · ˜J_{G2}(x,ξ) dξ_2) dξ_1 dx_1 … dx_4 · (dz_1/z_1) … (dz_8/z_8) equals 0, then the zero vector does not lie in the convex hull of Sp(f), where ˜J_{G2}(x,ξ)=ξ_1 ξ_2 [ξ_1^2(16(1−ξ_2^2)^3+9(1−ξ_2^2)−24(1−ξ_2^2)^2) − (1−ξ_1^2)(3ξ_2−4ξ_2^2)^2] [ξ_1^2(1−ξ_2^2) − (1−ξ_1^2)ξ_2^2] x_1 x_2 x_3 x_4 and Sp(f) is defined by the nonzero Fourier–Laurent exponents in the torus variables.

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Background

Using the SU(N)-based decomposition approach, the paper formulates an analogous conjecture for the exceptional Lie group G2, involving a specific Jacobian factor derived from the generalized Euler angles framework and the group’s structure.

As with SU(N) and Sp(N), the author states that the Mathieu Conjecture for G2 follows assuming the validity of this conjecture, thereby reducing the problem to an abelian integral criterion involving the spectrum of admissible functions.

References

Using Lemma \ref{lemma:Euler_Angles_SU(N)revisited} and the techniques given in this paper instead of Lemma 2.5 in , we arrive at the following two conjectures and theorems: Let $f:[0,1]{6}\times \mathbb{T}{8}\rightarrow$ be an admissible function in the sense of Definition \ref{def:admissible_function}. If $$\int{\mathbb{T}8}\int_{[0,1]5}\int_0{S(\xi_1)}fP \tilde{J}{G_2}\,d\xi_2 d\xi_1 dx_1\ldots dx_4\frac{dz_1}{z_1}\ldots\frac{dz_8}{z_8} = 0$$ for all $P\in $, where \begin{align} \begin{split} \tilde{J}{G_2}(x_1,\ldots,x_4,\xi_1,\xi_2):=& \xi_1\xi_2\bigg[\xi_12(16(1-\xi_22)3+9(1-\xi_22) -24(1-\xi_22)2)-\ & (1-\xi_12)(3\xi_2-4\xi_22)2\bigg]\big[\xi_12(1-\xi_22)-(1-\xi_12)\xi_22\big]x_1x_2x_3x_4,\end{split} \end{align} then $\vec{0}$ does not lie in the convex hull of $\mathrm{Sp}(f)$.

An addendum on the Mathieu Conjecture for $SU(N)$, $Sp(N)$ and $G_2$ (2504.01516 - Zwart, 2 Apr 2025) in Conjecture (label con:xz-conjecture_G_2), Section 3: Concerning the groups Sp(N) and G2