Painlevé I limit conjecture for the rescaled tau-function near the critical surface

From papers

The critical surface is parameterized by

{(t1(ς,η),t2±(ς,η),t5(ς,η)ηR, ς>max{53η,0}},\left\{(t_1(\varsigma,\eta),t_2^{\pm}(\varsigma,\eta),t_5(\varsigma,\eta)\mid \eta\in \operatorname{\mathbb{R}},\ \varsigma > \max\left\{\frac{5}{3}\eta,0\right\}\right\},

with

t1(ς,η)=512ς(5η9ης+3ς2),t2±(ς,η)=±2ς12(5η3ς)2,t5(ς,η)=η.t_1(\varsigma,\eta) = -\frac{5}{12}\varsigma\left(5\eta-9\eta\varsigma+3\varsigma^2\right),\qquad t_2^{\pm}(\varsigma,\eta) = \pm\frac{\sqrt{2\varsigma}}{12}(5\eta-3\varsigma)^2,\qquad t_5(\varsigma,\eta) = \eta.

Let P0=t1(0),t2±(0),t5(0)P_0 = \langle t_1^{(0)},t_2^{\pm (0)},t_5^{(0)}\rangle be a point on this surface, and let u=u1,u2,u5{\bf u} = \langle u_1,u_2,u_5\rangle be a unit vector based at P0P_0 lying in the region DD below the tangent plane of the critical surface. Define

X1(xT):=T6t1(0)+CT2/5u1x,X2(xT):=T5t2±(0)+CT3/5u2x,X5(xT):=T2t5(0)+CT18/5u5x.X_1(x|T):= T^6 t_1^{(0)} + C T^{2/5}u_1 x,\qquad X_2(x|T):= T^5 t_2^{\pm (0)} + C T^{-3/5}u_2 x,\qquad X_5(x|T):= T^2 t_5^{(0)} + C T^{-18/5}u_5 x.

Painlevé I limit conjecture. There exists a choice of constant C=C(P0,u)>0C = C(P_0,{\bf u})>0 and a polynomial Q(t1,t2,t5)Q(t_1,t_2,t_5) such that, defining τ^0:=eQ\hat{\tau}_0:= e^{Q}, considered as a differential in xx,

limTdlogτ(X5(xT),X2(xT),X1(xT))τ^0(X5(xT),X2(xT),X1(xT))=H(x)dx,\lim_{T\to \infty} {\bf d} \log \frac{\tau(X_5(x|T),X_2(x|T),X_1(x|T))}{\hat{\tau}_0(X_5(x|T),X_2(x|T),X_1(x|T))} = -\mathcal{H}(x)dx,

where H(x)\mathcal{H}(x) is the Painlevé I Hamiltonian. This asserts that a broad class of limits of the tau-function near the critical surface is governed by the Painlevé I Hamiltonian; the source provides no resolution status for this conjectural claim.

Progress summary

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Sources & referencesView supporting material

Primary source

Nathan Hayford, “Asymptotic Properties of a Special Solution to the (3,4) String Equation”, arXiv:2507.22646 (2025).

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