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Super and hyper products of super relations

In: Tatra Mountains Mathematical Publications, vol. 78, no. 1
Árpád Száz Číslo ORCID
Detaily:
Rok, strany: 2021, 85 - 118
Jazyk: eng
Kľúčové slová:
relations on ordinary and power sets, unary and binary operations for relations, Galois connections, generalized uniformities, generalized open sets.
Typ článku: Mathematics
Typ dokumentu: scientific paper
O článku:
If $R$ is a relation on $X$ to $Y$, $U$ is a relation on $\mathcal{P}(X)$ to $Y$, and $V$ is a relation on $\mathcal{P} (X)$ to $\mathcal{P} (Y)$, then we say that $R$ is an ordinary relation, $U$ is a super relation, and $V$ is a hyper relation on $X$ to $Y$.

\par Motivated by an ingenious idea of Emilia Przemska on a unified treatment of open- and closed-like sets, we shall introduce and investigate here four reasonable notions of product relations for super relations.

\par In particular, for any two super relations $U$ and $V$ on $X$, we define two super relations $U* V$ and $U* V$, and two hyper relations $U\pmb{\pmb{*}} V$ and $U\divideontimes V$ on $X$ such that :

\begin{align*} ( U* V ) (A) & = ( A\cup U (A) )\cap V (A), \\[1ex] ( U* V ) (A) & = ( A\cap V (A) )\cup U (A) \end{align*}

and

\begin{align*} ( U\pmb{\pmb{*}} V ) (A) & = \{B\subseteq X: (U* V ) (A)\subseteq B\subseteq (U* V ) (A) \}, \\[1ex] ( U\divideontimes V ) (A) & = \{B\subseteq X: ( U\cap V ) (A)\subseteq B\subseteq ( U\cup V ) (A) \} \end{align*}

\noindent for all $A\subseteq X$.

\par By using the distributivity of the operation $\cap$ over $\cup$, we can at once see that $U* V\subseteq U* V$. Moreover, if $U\subseteq V$, then we can also see that $U* V=U* V$. The most simple case is when $U$ is an interior relation on $X$ and $V$ is the associated closure relation defined such that $V (A)= U ( A\0c)\0c$ for all $A\subseteq X$.

Ako citovať:
ISO 690:
Száz, Á. 2021. Super and hyper products of super relations. In Tatra Mountains Mathematical Publications, vol. 78, no.1, pp. 85-118. 1210-3195. DOI: https://doi.org/10.2478/tmmp-2021-0007

APA:
Száz, Á. (2021). Super and hyper products of super relations. Tatra Mountains Mathematical Publications, 78(1), 85-118. 1210-3195. DOI: https://doi.org/10.2478/tmmp-2021-0007
O vydaní:
Vydavateľ: Mathematical Institute, Slovak Academy of Sciences, Bratislava
Publikované: 14. 10. 2021
Verejná licencia:
https://creativecommons.org/licenses/by-nc-nd/4.0/