I looked at definitions and questions already posed, but none helps in clarifying this specific challenge I am trying to understand.
Assume x $\in$ X = {1,2,3,4,5,6,8}
and I want
- inf{ x | x $\geq$ 5.5 } = 6
- sup{ x | x $\leq$ 5.5 } = 5
- inf{ x | x $\geq$ 8 } = 8
- sup{ x | x $\geq$ 8 } = 8
Is this correct? What I'm wary about is that some might argue that
- inf{ x | x $\geq$ 5.5 } = 5