Spectral gap

In mathematics, the spectral gap is the difference between the moduli of the two largest eigenvalues of a matrix or operator; alternately, it is sometimes taken as the smallest non-zero eigenvalue. Various theorems relate this difference to other properties of the system.

See:

• Expander graph (discrete case)
• Poincaré inequality (continuous case)

See also

• Spectral radius
• Eigengap