DiscreteDelta[n_1, n_2, ...] gives the discrete delta function \[Delta] (n_1, n_2, ...), equal to 1 if all the n_i are zero, and 0 otherwise.
DistributionParameterQ[dist] yields True if dist is a valid distribution, and yields False otherwise.
GradientFilter[image, r] gives an image corresponding to the magnitude of the gradient of image, computed using discrete derivatives of a Gaussian of pixel radius ...
InverseBetaRegularized[s, a, b] gives the inverse of the regularized incomplete beta function.
InverseErfc[s] gives the inverse complementary error function obtained as the solution for z in s = erfc(z).
InverseGammaRegularized[a, s] gives the inverse of the regularized incomplete gamma function.
MedianDeviation[list] gives the median absolute deviation from the median of the elements in list.
MemberQ
(Built-in Mathematica Symbol) MemberQ[list, form] returns True if an element of list matches form, and False otherwise. MemberQ[list, form, levelspec] tests all parts of list specified by levelspec.
NHoldAll is an attribute which specifies that none of the arguments to a function should be affected by N.
NormalizedSquaredEuclideanDistance[u, v] gives the normalized squared Euclidean distance between vectors u and v.