% TeX root = ../main.tex
\begin{tikzpicture}[program,initial above,font=\scriptsize]
    \node[state,initial]    (l0)                       {$\ell_0$};
    \node[state] (l1) [below=2cm of l0] {$\ell_1$};
    \node[state] (l2) [below=3cm of l1] {$\ell_2$};

    \path[->]   
        (l0) edge node { $t_0: \eta_0(x) = u $ } (l1)
        (l1) edge [out=110,in=150,looseness=10,draw=rot-75]
        node[swap]{$t_{1a}:\begin{aligned} p&=0.5 \\ \tau_1&= 1 \leq x \leq 3
        \Land w = 0\end{aligned}$} (l1)
        (l1) edge [out=160,in=200,looseness=10,draw=rot-75]
        node[swap]{$ t_{1b}: \begin{aligned}p&=0.5 \\ \tau_1&= 1 \leq x \leq 3
        \Land w = 0 \\ \eta_{1b}(x)&= x + 1\end{aligned}$} (l1)
        (l1) edge[bend left =30] node {$t_{2}:\tau_2 = y \geq 0
        \Land w = 1$} (l2)
        (l2) edge[bend left=30] node {$t_{3}: \eta_3(y) = y -
        \textsc{Bern}(0.5)$} (l1)
                    ;
\end{tikzpicture}