B. Magajna

activity

20032022

most citedDual operator systems

12 citations · 20 across the 14 of their papers we have counts for

collaborators

17 papers

math.FA2022

Orthonormal pairs of operators

Bojan Magajna

We consider pairs of operators $A, B \in B (H)$ , where $H$ is a Hilbert space, such that there exist a linear isometry $f$ from the span of ${A, B}$ into $C^{2}$ mapping $A, B$ …

math.OA2022

Which states can be reached from a given state by unital completely positive maps?

Bojan Magajna

For a state $ω$ on a C $^{*}$ -algebra $A$ we characterize all states $ρ$ in the weak* closure of the set of all states of the form $ω \circ φ$ , where $φ$ is a map on $A$ of the form $φ(…

math.RA2014

Bicommutants and Arens regularity

Bojan Magajna

Let $C$ and $R$ be unital rings and $Z$ an injective cogenerator for right $C$ -modules. For an $R, C$ -bimodule $U$ let $U^{*} = H o m_{C} (U, Z)$ , $S = E n d_{R} (U)$ and $B i e n d_{R} (U) = E n d_{S} (U)$ , the…

math.FA2013

Variance of operators and derivations

Bojan Magajna

The variance of a bounded linear operator $a$ on a Hilbert space $H$ at a unit vector $h$ is defined by $D_{h} (a) = ∥ ah ∥^{2} - ∣ < ah, h > ∣^{2}$ . We show that two operators $a$ and $b$ have th…

math.RA2012

Bicommutants and ranges of derivations

Bojan Magajna

Let $V$ be a vector space over a field $F$ , $V^{*}$ its dual space and $L (V)$ the algebra of all linear operators on $V$ . For an operator $a \in L (V)$ let $a *$ be its adjoint acting o…

math.OA2012

Identifying derivations through the spectra of their values

M. Brešar, B. Magajna, Š. Špenko

We consider the relationship between derivations $d$ and $g$ of a Banach algebra $B$ that satisfy $\s(g(x)) \subseteq \s(d(x))$ for every $x \in B$ , where $\s(\, . \,)$ stands for t…