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arXiv · 1604.03544

Ramanujan Graphs in Polynomial Time

Michael B. Cohen
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Abstract

The recent work by Marcus, Spielman and Srivastava proves the existence of bipartite Ramanujan (multi)graphs of all degrees and all sizes. However, that paper did not provide a polynomial time algorithm to actually compute such graphs. Here, we provide a polynomial time algorithm to compute certain expected characteristic polynomials related to this construction. This leads to a deterministic polynomial time algorithm to compute bipartite Ramanujan (multi)graphs of all degrees and all sizes.

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Michael B. Cohen. 2016-04-12. Ramanujan Graphs in Polynomial Time. https://arxiv.org/abs/1604.03544

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