09 Feb '15 11:023 edits

I have been reading this:

http://en.wikipedia.org/wiki/Sigma_additivity#Additive_.28or_finitely_additive.29_set_functions

and, in the main, understanding it although there are some aspects of it that I still struggle with.

But, I really want to better understand it is at least just a couple of different examples of mathematical functions u defined on an algebra of sets A with values in [−∞, +∞] that are NOT additive complete with explanations of

Anyone?

http://en.wikipedia.org/wiki/Sigma_additivity#Additive_.28or_finitely_additive.29_set_functions

and, in the main, understanding it although there are some aspects of it that I still struggle with.

But, I really want to better understand it is at least just a couple of different examples of mathematical functions u defined on an algebra of sets A with values in [−∞, +∞] that are NOT additive complete with explanations of

*why*they are not additive if that*why*isn't self-evident.Anyone?