Real Analysis Help

[prometheus54]

I need help to prove the following.
Let A and B be nonempty subsets of R such that a<= b for all a? A and all b ? B, then sup A < =inf B. Any help would be appreciated, thanks.

 

[tkhunny]

At this level, we would do youa disservice by letting you get away with no effort. Check your definitions of "<" and "inf" and come up with something. There are many who will guide you, but you must get started.

 

[prometheus54]

Well i understand what the problem is saying, and it seems obvious, that the sup A<=inf B, but thats exactly my problem I do not know how to get started.