In functional analysis and related areas of mathematics an FK-AK space or FK-space with the AK property is an FK-space which contains the space of finite sequences and has a Schauder basis. Examples and non-examples the space of convergent sequences with the supremum norm has the AK property. () the absolutely p-summable sequences with the norm have the AK property. with the supremum norm does not have the AK property. Properties An FK-AK space has the property that is the continuous dual of is linear isomorphic to the beta dual of FK-AK spaces are separable spaces. See also References Topological vector spaces