A Banach space not containing $l_{1}$ whose dual ball is not weak${}^\ast$ sequentially compact

DOUBLE - DUAL n - TYPES OVER BANACH SPACES NOT CONTAINING

Let E be a Banach space. The concept of n-type over E is introduced here, generalizing the concept of type over E introduced by Krivine and Maurey. Let E′′ be the second dual of E and fix g′′ 1 , . . . ,g′′ n ∈ E′′. The function τ : E×Rn → R, defined by letting τ(x,a1, . . . ,an) = ‖x+∑ni=1aig′′ i ‖ for all x ∈ E and all a1, . . . ,an ∈R, defines an n-type over E. Types that can be represented ...

Double-dual n-types over Banach spaces not containing ℓ1

Let E be a Banach space. The concept of n-type over E is introduced here, generalizing the concept of type over E introduced by Krivine and Maurey. Let E′′ be the second dual of E and fix g′′ 1 , . . . ,g′′ n ∈ E′′. The function τ : E×Rn → R, defined by letting τ(x,a1, . . . ,an) = ‖x+∑ni=1aig′′ i ‖ for all x ∈ E and all a1, . . . ,an ∈R, defines an n-type over E. Types that can be represented ...

The ideal completion is not sequentially adequate

It is well known that for the case of a countable partial order, the ideal completion and the chain completion coincide. We investigate the boundary at which the chain and ideal completion do not coincide. We show in particular that the ideal completion is not sequentially adequate; that is it is not possible in general to simply replace the ideal completion with a completion based on sequences...

A not on modular hyperconvex space

SEQUENTIALLY COMPACT S-ACTS

‎‎The investigation of equational compactness was initiated by‎ ‎Banaschewski and Nelson‎. ‎They proved that pure injectivity is‎ ‎equivalent to equational compactness‎. ‎Here we define the so‎ ‎called sequentially compact acts over semigroups and study‎ ‎some of their categorical and homological properties‎. ‎Some‎ ‎Baer conditions for injectivity of S-acts are also presented‎.