Oscillating kernel

A function $ K( x, s) $, $ a \leq x, s \leq b $, such that for any points $ x _ {1} \dots x _ {n} \in [ a, b] $, which (when $ n= 2 $) include at least one interior point, the matrix $ \| K( x _ {i} , x _ {k} ) \| _ {1} ^ {n} $ is an oscillating matrix.

References

[a1]	F.R. Gantmakher, M.G. Krein, "Oscillation matrices and kernels and small vibrations of mechanical systems" , Dept. Commerce USA. Joint Publ. Service (1961) (Translated from Russian)
[a2]	S. Karlin, "Total positivity" , Stanford Univ. Press (1960)