FK-AK space

• ${\displaystyle c_{0}}$ the space of convergent sequences with the supremum norm has the AK property.
• ${\displaystyle \ell ^{p}}$ (${\displaystyle 1\leq p<\infty }$) the absolutely p-summable sequences with the ${\displaystyle \|\cdot \|_{p}}$ norm have the AK property.
• ${\displaystyle \ell ^{\infty }}$ with the supremum norm does not have the AK property.

An FK-AK space ${\displaystyle E}$ has the property

$${\displaystyle E'\simeq E^{\beta }}$$

that is the continuous dual of ${\displaystyle E}$ is linear isomorphic to the beta dual of ${\displaystyle E.}$

FK-AK spaces are separable spaces.

• BK-space – Sequence space that is Banach
• FK-space – Sequence space that is Fréchet
• Normed space – Vector space on which a distance is definedPages displaying short descriptions of redirect targets
• Sequence space – Vector space of infinite sequences