arXiv subjects

Hitomi Terajima

Publications and source records attributed to Hitomi Terajima.

3 recordsLinked to original sources

arXiv2002

Nodal curves and Riccati solutions of Painlevé equations

In this paper, we study Riccati solutions of Painlevé equations from a view point of geometry of Okamoto-Painlevé pairs $(S,Y)$. After establishing the correspondence between (rational) nodal curves on $S-Y$ and Riccati solutions, we give the complete classification of the configurations of nodal curves on $S-Y$ for each Okamoto-Painlevé pair $(S, Y)$. As an application of the classification, we prove the non-existence of Riccati solutions of Painlevé equations of types $P_{I}, P_{III}^{\tilde{D}_8}$ and $P_{III}^{\tilde{D}_7}$. We will also give a partial answer to the conjecture in (STT) and (T) that the dimension of the local cohomology $H^1_{Y_{red}}(S,Θ_S(-\log Y_{red}))$ is one.

math.AG↗

arXiv2000

Deformation of Okamoto-Painlevé Pairs and Painlevé equations

In this paper, we introduce the notion of generalized rational Okamoto-Painlevé pair (S, Y) by generalizing the notion of the spaces of initial conditions of Painlevé equations. After classifying those pairs, we will establish an algebro-geometric approach to derive the Painlevé differential equations from the deformation of Okamoto-Painlevé pairs by using the local cohomology groups. Moreover the reason why the Painlevé equations can be written in Hamiltonian systems is clarified by means of the holomorphic symplectic structure on S - Y. Hamiltonian structures for Okamoto-Painlevé pairs of type $\tilde{E}_7 (= P_{II})$ and $\tilde{D}_8 (= P_{III}^{\tilde{D}_8})$ are calculated explicitly as examples of our theory.

math.AG↗

arXiv2000

Local cohomology of generalized Okamoto-Painlevé pairs and Painlevé equations

In the theory of deformation of Okamoto-Painlevé pair (S,Y), a local cohomology group $H^1_D(Θ_S(-\log D))$ plays an important role. In this paper, we estimate the local cohomology group of pair (S,Y) for several types, and obtain the following results. For a pair (S,Y) corresponding to the space of initial conditions of the Painlevé equations, we show that the local cohomology group $H^1_D(Θ_S(-\log D))$ is at least 1 dimensional. This fact is the key to understand Painlevé equation related to (S,Y). Moreover we show that, for the pairs (S,Y) of type $\tilde{A_8}$, the local cohomology group $H^1_D(Θ_S(-\log D))$ vanish. Therefore in this case, there is no differential equation on S-Y in the sense of the theory.

math.AG↗