Singular integral - Wikipedia
https://en.wikipedia.org/wiki/Singular_integralThese are even more general operators. However, since our assumptions are so weak, it is not necessarily the case that these operators are bounded on L . A function K : R ×R → R is said to be a Calderón–Zygmund kernel if it satisfies the following conditions for some constants C > 0 and δ > 0. T is said to be a singular integral operator of non-convolution type associated to the Calderón–Z…
Singular integral - Wikipedia
en.wikipedia.org › wiki › Singular_integralIn mathematics, singular integrals are central to harmonic analysis and are intimately connected with the study of partial differential equations. Broadly speaking a singular integral is an integral operator. T ( f ) ( x ) = ∫ K ( x , y ) f ( y ) d y , {\displaystyle T (f) (x)=\int K (x,y)f (y)\,dy,} whose kernel function K : Rn × Rn → R is singular along the diagonal x = y.