PageHeader : Funkcialaj Ekvacioj, 30 (1987) 305-332 Title : Studies on the Painleve Equations IV. Title : Third Painleve Equation $\mathrm{P}_{III}$ AuthorInfo : By AuthorInfo : Kazuo OKAMOTO AuthorInfo : (University of Tokyo, Japan) section : Introduction section : 1. Painleve system subsection : 1.1. Painleve equation $\mathrm{P}_{III^{\prime}}$ subsection : 1.2. Painleve system $\mathscr{H}_{III^{\prime}}$ subsection : 1.3. Symmetry of the Hamiltonian $\mathscr{H}_{III^{\prime}}$ subsection : 1.4. Auxiliary Hamiltonian function subsection : 1.5. Painleve system $\mathscr{H}_{III}$ section : 2. Transformation group of $\mathscr{H}_{III^{\prime}}$ subsection : 2.1. Root system subsection : 2.2. Weyl group $\mathrm{W}$ subsection : 2.3. Involution of $\mathrm{E}$ subsection : 2.4. Auxiliary functions subsection : 2.5. Parallel transformation $\ell$ subsection : 2.6. Realization of $s_{0}$ as the the canonical transformation section : 3. Toda equation and -functions subsection : 3.1. -function subsection : 3.2. Proof of Proposition 0.1 subsection : 3.3. Painleve transcendental function and -function subsection : 3.4. Toda equation subsection : 3.5. Proof of Theorem 2 section : 4. Cylinder function and Painleve transcendental function subsection : 4.1. Classical solution subsection : 4.2. Transformation $\ell_{*}^{-1}$ in the degenerate case subsection : 4.3. Sequence ofthe cylinder functions section : References