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On The Paper "Regular Equivalence Relations On Ordered $*$-Semihypergroups", Niovi Kehayopulu
On The Paper "Regular Equivalence Relations On Ordered $*$-Semihypergroups", Niovi Kehayopulu
Turkish Journal of Mathematics
If $(S,\circ,\le)$ is an ordered hypersemigroup, an equivalence relation $\rho$ on $S$ is called congruence if $(a,b)\in\rho$ implies $(a\circ x, b\circ x)\in\rho$ and $(x\circ a, x\circ b)\in\rho$ for every $x\in S$; in the sense that for every $u\in a\circ x$ there exists $v\in b\circ x$ such that $(u,v)\in\rho$ and for every $u\in x\circ a$ there exists $v\in x\circ b$ such that $(u,v)\in\rho$. It has been proved in Turk J Math 2021(5) [On the paper "A study on (strong) order-congruences in ordered semihypergroups"] that if $S$ is an ordered hypersemigroup, then there exists a congruence $\rho$ on $S$ such that $S/\rho$ …
On The Paper ``A Study On (Strong) Order-Congruences In Ordered Semihypergroups", Niovi Kehayopulu
On The Paper ``A Study On (Strong) Order-Congruences In Ordered Semihypergroups", Niovi Kehayopulu
Turkish Journal of Mathematics
Throughout the paper in the title by Jian Tang, Yanfeng Luo and Xiangyun Xie in Turk J Math 42 (2018) the following lemma has been used. Lemma: Let $(S,*)$ be a semihypergroup and $\rho$ an equivalence relation on S. Then $(i)$ If $\rho$ is a congruence, then $(S/\rho,\otimes)$ is a semihypergroup with respect to the hyperoperation $(a)_\rho\otimes (b)_\rho=\bigcup\limits_{c\in a*b} {(c)_\rho}$. $(ii)$ If $\rho$ is a strong congruence, then $(S/\rho,\otimes)$ is a semigroup with respect to the operation $(a)_\rho\otimes (b)_\rho=(c)_\rho$ for all $c\in a*b$.} The property (i) of the paper is certainly wrong as $\bigcup\limits_{c\in a*b} {(c)_\rho}$ is a subset of …