Guiduli's spectral dense-neighborhood conjecture
Guiduli's spectral dense-neighborhood conjecture
Let be a graph on vertices, let denote the Turán graph, let denote the neighborhood of a vertex , let denote its degree, and let denote the spectral radius of . Guiduli's spectral dense-neighborhood conjecture. If
then either , or there is a vertex such that
Furthermore, if
then the conclusion holds for any vertex having maximum weight given by a positive eigenvector for . The conjecture is presented as a spectral analogue of the dense-neighborhood theorem of Bollobás and Thomason and Erdős and Sós, which proved the corresponding ordinary Turán statement. The supplied text does not state whether Guiduli's spectral conjecture has been resolved.
Sources & referencesView supporting material
Primary source
Lele Liu and Bo Ning, “On spectral Turán theorems: confirming a conjecture of Guiduli and two problems of Nikiforov”, arXiv:2605.05048 (2026).
Progress summary
Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.
Solutions 0
Sign in to submit a solution.
No solutions have been posted yet.