Saak Gabriyelyan

Dunford—Pettis type properties of locally convex spaces.

Being motivated by the Dunford—Pettis property (the DP property) and the strict Dunford—Pettis property (the strict DP property) introduced by Grothendieck in the realm of locally convex spaces and by the DP property of order p\in[1,\infty] for Banach spaces introduced by Castillo and Sanchez, we define the quasi Dunford—Pettis property of order p (the quasi DP_p property) and the sequential Dunford—Pettis property of order (p,q) (the sequential DP_{(p,q)} property).

We show that a locally convex space (lcs) E has the DP property iff the space E endowed with the Grothendieck topology \tau_{\Sigma'} has the weak Glicksberg property, and E has the quasi DP_p property iff the space (E,\tau_{\Sigma'}) has the p-Schur property. We also characterize lcs with the sequential DP_{(p,q)} property. We give the first example of an lcs with the strict DP property but without the DP property and show that the completion of even normed spaces with the DP property may not have the DP property.