Come on, you know how things work on MathHelpForum.
Please either post some of your own work on this problem or explain what you do not understand about the question.
For a nonempty set B that is a subset of the Real Numbers, one can define the greatest lower bound inf(B) (for infimum) of B. Give the precise definition for inf(B) and prove that it is unique if it exists. Also define min(B)
Thanks for the help!