x_{1} is a Kronecker delta function defined on structure x_{2} which evaluates to one for any argument belonging to subset x_{3} and which evaluates to zero otherwise

x2 determines domain, codomain, and the meaning of "zero" and "one". x3 is a set; for the typical usage of delta(x,n) for fixed n, let x3 be the singleton set such that n is an element thereof.

- ma'au
- Binary mekso operator: uniform probability A(X
_{2)u(X}for input (X_{1,X}where X_{1}is a number and X_{2}is a set or space. (See notes for details). - faunjdikpe
- x
_{1}(function) is the restriction of function x_{2}to domain set x_{3}