Kazan (Volga region) Federal University, KFU
KAZAN
FEDERAL UNIVERSITY
 
ON INDEPENDENCE OF EVENTS IN NONCOMMUTATIVE PROBABILITY THEORY
Form of presentationArticles in international journals and collections
Year of publication2021
Языканглийский
  • Bikchentaev Ayrat Midkhatovich, author
  • Ivanshin Petr Nikolaevich, author
  • Bibliographic description in the original language A. M. Bikchentaev, P. N. Ivanshin, On Independence of Events in Noncommutative Probability Theory // Lobachevskii Journal of Mathematics, 2021, Vol. 42, No. 10, pp. 2306–2314.
    Annotation We consider a tracial state $\varphi$ on a von Neumann algebra $\mathcal{A}$ and assume that projections $P, Q$ of $\mathcal{A}$ are independent if $\varphi (PQ)=\varphi (P)\varphi (Q)$. First we present the general criterion of a projection pair independence. We then give a geometric criterion for independence of different pairs of projections. If atoms $P$ and $Q$ are independent then $\varphi (P)= \varphi (Q)$. Also here we deal with an analog of a ``symmetric difference'' for a pair of projections $P$ and $ Q$, namely, the projection $ R\equiv P\vee Q -P\wedge Q$. If $R\neq 0, I$, the pairs $\{P, R\}$ and $ \{Q, R\}$ are independent then $\varphi (P)= \varphi (Q)=1/2$ and $\varphi ( P\wedge Q + P\vee Q) =1$. If, moreover, $P$ and $ Q $ are independent, then $\varphi ( P\wedge Q)\leq 1/4$ and $\varphi ( P\vee Q)\geq 3/4$. For an atomless von Neumann algebra $\mathcal{A}$ a tracial normal state is determined by its specification of independent events. We clarify our considerations with examples of projection pairs with the differemt mutual independency relations. For the full matrix algebra we give several equivalent conditions for the independence of pairs of projections.
    Keywords Hilbert space, linear operator, projection, von Neumann algebra, tracial state, independence.
    The name of the journal Lobachevskii Journal of Mathematics
    Please use this ID to quote from or refer to the card https://repository.kpfu.ru/eng/?p_id=255107&p_lang=2
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