Showing posts with label Characteristic function. Show all posts
Showing posts with label Characteristic function. Show all posts

Sunday, January 4, 2009

Step Functions

Step functions can be seen as generalizations of characteristic functions.

Step functions can be expressed as b = {b sub a such that a has multiple definitions)

For example consider a set M equal to a coordinate [1,5] expressed on multiple sets Bsub1=[1,2]
Bsub2=[2,4]
Bsub3=[4,5]

Now let all the sub numbers be defined on the y axis as follows
Ysub(1)=3
Ysub(2)=4
Ysub(3)=2

The resulting graph would be a series from 1 to 5 on the horizontal x axis (set A) with a line going from 1 to 2 at point 3 on the y axis, and another line going from 2 to 4 at point 4 on the y axis, and then another line completing the "step" to 5 from 4 to 5 at point 2 on the y axis.

Saturday, January 3, 2009

Characteristic Functions

Characteristic functions define the functions of sets and the functions of all object outside the set.

Take for consideration the set A that is part of the Universe. Then the characteristic function can be seen as

f(x)={1 if x is an element of A, and 0 if x is an element of everything but A, (or U-A)}.