M. Johanis

activity

20162024

collaborators

3 papers

math.FA2024

Remarks on the point character of Banach spaces and non-linear embeddings into~$c_0(\Ga)$

Petr Hajek, Michal Johanis, Th. Schlumprecht

We give a brief survey of the results on coarse or uniform embeddings of Banach spaces into $c_0(\Ga)$ and the point character of Banach spaces. In the process we prove several new…

math.FA2023

On Whitney-type extension theorems on Banach spaces for $C^{1, ω}$ , $C^{1, +}$ , $C_{loc}^{1, +}$ , and $C_{B}^{1, +}$ -smooth functions

Michal Johanis, Václav Kryštof, Luděk Zajíček

Our paper is a complement to a recent article by D. Azagra and C. Mudarra (2021). We show how older results on semiconvex functions with modulus $ω$ easily imply extension theorems…

math.FA2016

Isometric embedding of $ℓ_{1}$ into Lipschitz-free spaces and $ℓ_{\infty}$ into their duals

Marek Cúth, Michal Johanis

We show that the dual of every infinite-dimensional Lipschitz-free Banach space contains an isometric copy of $ℓ_{\infty}$ and that it is often the case that a Lipschitz-free Bana…

Remarks on the point character of Banach spaces and non-linear embeddings into~$c_0(\Ga)$

On Whitney-type extension theorems on Banach spaces for C1,ω, C1,+, Cloc1,+​, and CB1,+​-smooth functions

Isometric embedding of ℓ1​ into Lipschitz-free spaces and ℓ∞​ into their duals

On Whitney-type extension theorems on Banach spaces for $C^{1, ω}$ , $C^{1, +}$ , $C_{loc}^{1, +}$ , and $C_{B}^{1, +}$ -smooth functions

Isometric embedding of $ℓ_{1}$ into Lipschitz-free spaces and $ℓ_{\infty}$ into their duals