Combinatorics · Oct 6, 2026
Deterministic nonbipartite Ramanujan graphs in every fixed degree
For every fixed d ≥ 3, constructs a simple d-regular nonbipartite Ramanujan graph on every sufficiently large even number n of vertices, with every nonconstant adjacency eigenvalue strictly between and . A deterministic algorithm outputs the full adjacency list in polynomial bit time, with exponent depending on d.
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