Difference between role, task and operation

I was wondering what exactly is the difference between those tree things: role, task and operation in AuthManager.

Are they included to Yii just to make Auth-hierarchy more readable? Becouse the funcionality of those tree elements seems to be igual(Looking in class reference).

I was just thinking that could you make all Autrozition hierarchy using only operations, tasks or roles just by using childItems? Am I Right?

Same doubt here

As you noticed, there are absolutely no difference at all.

Is just a question of readability but, at my glance, it gives no advantages, and I usually use only roles + child items.

Hey Thanks a lot to clear my doubts!

Glad to help you!