The nonsingularity conjecture for random regular graph adjacency matrices

Let Gn,dG_{n,d} be a uniformly random simple dd-regular graph on nn vertices, and let An,dA_{n,d} be its adjacency matrix.

Random regular graph singularity conjecture. For every 3dn13\leq d\leq n-1, An,dA_{n,d} is nonsingular with probability 1o(1)1-o(1).

The conjecture was raised by Vu and later appeared in work of Frieze and Vu. The source reports that the symmetric case has since been solved, so this conjecture is solved.

Equivalent formulations 1

Other statements of this same problem, merged from separate entries. Each is equivalent to the statement above — proving any one settles them all.

  1. Nonsingularity conjecture for random regular graph adjacency matrices

    Let Qn,dQ_{n,d} be the adjacency matrix of a uniformly random simple dd-regular graph on nn vertices. Random regular nonsingularity conjecture. For every d3d\ge 3, Qn,dQ_{n,d} is almost surely nonsingular. The source contrasts this with the case d=2d=2, where the adjacency matrix is almost surely singular because the graph is a union of cycles. No resolution is supplied for the stated range d3d\ge3.

    source: V. Vu, “Random Discrete Matrices”, arXiv:math/0611321 (2006).

Sources & referencesView supporting material

Primary source

Van Vu, “Recent progress in combinatorial random matrix theory”, arXiv:2005.02797 (2020).

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