Hobby–Rice theorem
= Hobby–Rice theorem
{wiki=Hobby–Rice_theorem}
The Hobby–Rice theorem is a result in the field of functional analysis, specifically related to the theory of compact operators on Banach spaces. The theorem provides conditions under which a certain type of operator can be approximated by finite-rank operators, which are often easier to deal with. The theorem is essentially a characterization of weakly compact sets in certain contexts.