33 citations · 95 across the 33 of their papers we have counts for
38 papers
Kalton-Peck space is not isomorphic to its hyperplanes
A. Das, V. Ferenczi, Ch. Rosendal
Let denote the real Kalton-Peck space. No hyperplane of admits a complex structure, and is even in the sense of Ferenczi-Galego. Therefore, is not linearly…
Envelopes in Banach spaces
Valentin Ferenczi, Jordi Lopez-Abad
We define the notion of isometric envelope of a subspace in a Banach space, and relate it to a) the mean ergodic projection on the space of fixed points of a semigroup of contracti…
On Mazur rotations problem and its multidimensional versions
Félix Cabello Sánchez, Valentin Ferenczi, Beata Randrianantoanina
The article is a survey related to a classical unsolved problem in Banach space theory, appearing in Banach's famous book in 1932, and known as the Mazur rotations problem. Althoug…
There is no largest proper operator ideal
Valentin Ferenczi
An operator ideal is proper if the only operators of the form it contains have finite rank. We answer a question posed by Pietsch (1979) by proving that there is no largest…
Group actions on twisted sums of Banach spaces
Jesús M. F. Castillo, Valentin Ferenczi
We study bounded actions of groups and semigroups on exact sequences of Banach spaces from the point of view of quasilinear maps, characterize the actions on the twisted sum sp…
Differential processes generated by two interpolators
J. M. F. Castillo, W. H. G. Correa, V. Ferenczi +1
We study couples of interpolators, the differentials they generate and their associated commutator theorems. An essential part of our analysis is the study of the intrinsic symmetr…