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arXiv · 2210.06363

On Extremal Rates of Storage over Graphs

Zhou Li·Hua Sun
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Abstract

A storage code over a graph maps $K$ independent source symbols, each of $L_w$ bits, to $N$ coded symbols, each of $L_v$ bits, such that each coded symbol is stored in a node of the graph and each edge of the graph is associated with one source symbol. From a pair of nodes connected by an edge, the source symbol that is associated with the edge can be decoded. The ratio $L_w/L_v$ is called the symbol rate of a storage code and the highest symbol rate is called the capacity. We show that the three highest capacity values of storage codes over graphs are $2, 3/2, 4/3$. We characterize all graphs over which the storage code capacity is $2$ and $3/2$, and for capacity value of $4/3$, necessary condition and sufficient condition (that do not match) on the graphs are given.

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Zhou Li, Hua Sun. 2022-10-12. On Extremal Rates of Storage over Graphs. https://arxiv.org/abs/2210.06363

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