The mean square deviation of the best local fit straight line to a staircase cumulative spectral density over a normalized energy scale.
Spectral Rigidity
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References
Ott, E. Chaos in Dynamical Systems. New York: Cambridge University Press, p. 341, 1993.Referenced on Wolfram|Alpha
Spectral RigidityCite this as:
Weisstein, Eric W. "Spectral Rigidity." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/SpectralRigidity.html