mapping -
(mathematics) a mathematical relation such that each element of a given set (the domain of the function) is associated with an element of another set (the range of the function)
expansion the act of increasing (something) in size or volume or quantity or scope
inverse function a function obtained by expressing the dependent variable of one function as the independent variable of another; f and g are inverse functions if f(x)=y and g(y)=x
kronecker delta a function of two variables i and j that equals 1 when i=j and equals 0 otherwise
metric function,
metric a function of a topological space that gives, for any two points in the space, a value equal to the distance between them
transformation the act of changing in form or shape or appearance; "a photograph is a translation of a scene onto a two-dimensional surface"
isometry equality of measure (e.g., equality of height above sea level or equality of loudness etc.)
operator an agent that operates some apparatus or machine; "the operator of the switchboard"
