 For a data set or signal of "N" variables, its intrinsic dimension "M" satisfies "0 ≤ M ≤ N".Let "formula_1" be a two-variable function (or signal) which is of the form

formula_2

for some one-variable function "g" which is not constant.This means that "f" varies, in accordance to "g", with the first variable or along the first coordinate.