A complete normed vector space (V, ‖·‖). Hahn–Banach, open mapping, closed graph, and uniform boundedness theorems form the four pillars of linear functional analysis on Banach spaces.
A complete normed vector space (V, ‖·‖). Hahn–Banach, open mapping, closed graph, and uniform boundedness theorems form the four pillars of linear functional analysis on Banach spaces.