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This paper studies the strong fractional choice number $ch^s_f(G)$ and thestrong fractional paint number $\chi^s_{f,P}(G)$ of a graph $G$. We prove thatthese parameters of any finite graph are rational numbers. On the other hand,for any positive integers $p,q$ satisfying $2 \le \frac{2p}{2q+1} \leq\lfloor\frac{p}{q}\rfloor$, there exists a graph $G$ with $ch^s_f(G) =\chi^s_{f,P}(G) = \frac{p}{q}$. The relationship between $\chi^s_{f,P}(G)$ and$ch^s_f(G)$ is explored. We prove that the gap $\chi^s_{f,P}(G)-ch^s_f(G)$ canbe arbitrarily large. The strong fractional choice number of a family$\mathcal{G}$ of graphs is the supremum of the strong fractional choice numberof graphs in $\mathcal{G}$. Let $\mathcal{P}$ denote the class of planar graphsand $\mathcal{P}_{k_1,\ldots, k_q}$ denote the class of planar graphs without$k_i$-cycles for $i=1,\ldots, q$. We prove that $3 + \frac{1}{2} \leqch^s_f(\mathcal{P}_{ 4}) \leq 4$, $ch^s_f(\mathcal{P}_{ k})=4$ for $k \in\{5,6\}$, $3 +\frac{1}{12} \leq ch^s_f(\mathcal{P}_{ 4,5}) \leq 4$ and$ch^s_f(\mathcal{P}) \ge 4+\frac 13$. The last result improves the lower bound$4+\frac 29$ in [X. Zhu, multiple list colouring of planar graphs, Journal ofCombin. Th. Ser. B,122(2017),794-799].

The strong fractional choice number and the strong fractional paint number of graphs