Syntax (summary)
-
f, g, h, Score, … names of functions
-
f : X ® Y, X
= domain( f ), Y = range( f )
-
Function definitions using tables and graphs
-
[X ® Y], set of all functions from
X into Y, is a function space.
-
A system is a function on function spaces: s: [X ®
Y] ® [W ®
Z].
Warning A function f is different from its value f(x)
at a point x. So it is incorrect to write something like: "let f(x)
be a function". Also, the information carried by a signal is contained
in the whole function and not in its value at one point.