activity
20242026
collaborators

7 papers

math.OA2026

On the embeddings of selfadjoint operator spaces

Alexandros Chatzinikolaou, Evgenios T. A. Kakariadis, Se-Jin Kim +1

We investigate when a map on a selfadjoint operator space is an embedding, i.e., when its unitisation in the sense of Werner is completely isometric. Combining with results of…

math.OA2026

Operator systems and positive extensions over discrete groups

Evgenios T. A. Kakariadis, Malte Leimbach, Ivan G. Todorov +1

The extension problem asks whether positive semi-definite functions on a symmetric unital subset of a discrete group can be extended to positive semi-definite functions on the whol…

math.OA2026

On hyperrigidity and non-degenerate C*-correspondences

Joseph A. Dessi, Evgenios T. A. Kakariadis, Ioannis Apollon Paraskevas

We revisit the results of Kim, and of Katsoulis and Ramsey concerning hyperrigidity for non-degenerate C*-correspondences. We show that the tensor algebra is hyperrigid, if and onl…

math.OA2026

Morita equivalence for operator systems

George K. Eleftherakis, Evgenios T. A. Kakariadis, Ivan G. Todorov

We define -equivalence for operator systems and show that it is identical to stable isomorphism. We define -contexts and bihomomorphism contexts and show that two operator…

math.OA2025

Symmetrisations of operator spaces

George K. Eleftherakis, Evgenios T. A. Kakariadis, Ivan G. Todorov

Let be a unital C*-algebra, be an operator -system and be an operator space that is a left operator -module. We introduce the symmetrisation of the pair a…

math.OA2025

On Fock covariance for product systems and the reduced Hao-Ng isomorphism problem by discrete actions

Evgenios T. A. Kakariadis, Ioannis Apollon Paraskevas

We provide a characterisation of equivariant Fock covariant injective representations for product systems. We show that this characterisation coincides with Nica covariance for com…