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Succinct Data Structure for Graphs with d-Dimensional t-Representation

Succinct Data Structure for Graphs with d-Dimensional t-Representation

Date4th Mar 2024

Time11:00 AM

Venue A M Turing Hall (SSB 334, Second Floor)

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Details

Erdos and West (Discrete Mathematics'85) considered the class of n vertex intersection graphs which have a d$-dimensional t-representation, that is, each vertex of a graph in the class has an associated set consisting of at most t d-dimensional axis-parallel boxes. In particular, for a graph G and for each d \geq 1, they consider i_d(G) to be the minimum t for which G has such a representation. For fixed t and d, they consider the class of n vertex labeled graphs for which i_d(G) \leq t, and prove an upper bound of (2nt+\frac{1}{2})d \log n - (n - \frac{1}{2})d \log(4\pi t) on the logarithm of size of the class.

In this work, for fixed t and d we consider the class of n vertex unlabeled graphs which have a d-dimensional t-representation, denoted by \mathcal{G}_{t,d}. We address the problem of designing a succinct data structure for the class \mathcal{G}_{t,d} in an attempt to generalize the relatively recent results on succinct data structures for interval graphs (Algorithmica'21). To this end, for each n such that td^2 is in o(n / \log n), we first prove a lower bound of (2dt-1)n \log n - O(ndt \log \log n)-bits on the size of any data structure for encoding an arbitrary graph that belongs to \mathcal{G}_{t,d}.

We then present a ((2dt-1)n \log n + dt\log t + o(ndt \log n))-bit data structure for \mathcal{G}_{t,d} that supports navigational queries efficiently. Contrasting this data structure with our lower bound argument, we show that for each fixed t and d, and for all n \geq 0 when td^2 is in o(n/\log n) our data structure for \mathcal{G}_{t,d} is succinct.

As a byproduct, we also obtain succinct data structures for graphs of bounded boxicity (denoted by d and t = 1) and graphs of bounded interval number (denoted by t and d=1) when td^2 is in o(n/\log n).

Speakers

Mr. Girish Balakrishnan, Roll No: CS19D012

Computer Science and Engineering