function definition, function and relation instance, function operation and SQL, experiment and relation example in probability theory

A function is a collection in which each element is a two-tuple or multivariate group. For example F = {(x, y) | X∈r & y∈r & y = 2x}, g = {(x, y, z) | (x, Y, z) ∈r3 & z = 2x + 3y}, symbols F and G refer to two functions.

A relationship instance is a collection, and each element of it is a tuple. You can see that relationship instances and functions are almost the same concept, except that each element of a function cannot be a tuple, and the relationship instance has no such constraint.

One experiment is a tuple, and each of its elements refers to an event.

Example: Finding the maximum value of a function

Known function f = {(x, y, z) | (x, z) ∈r3 and z = x2-y2}

So minxmaxyf =

SelectT.x from(Selectf.x, F.y fromFwheref.x, F.zinch(SelectF.x,Max(F.Z) fromFGroup  byf.x)) asTwhereT.y=(Select min(T.Y) fromT);

function definition, function and relation instance, function operation and SQL, experiment and relation example in probability theory