Quasi-Order Hypergroups and T-Hypergroups

Quasi-order hypergroups were introduced by J. Chvalina in 90s of the lastcentury. They form a subclass of the class of all hypergroups, i.e. structureswith one associative hyperoperation fulfilling the reproduction axiom. In thispaper a theorem which allows an easy description of all quasi-order hyper-groups is mentioned and some results concerning the relation of quasi-orderand upper quasi-order hypergroups are given. Furthermore the transformationhypergroups acting on tolerance spaces are defined and an example of them isgive