A natural loop structure is defined on the set of unimodular upper-triangular matrices over a given field. Inner mappings of the loop are computed. It is shown that the loop is non-associative and nilpotent, of class 3. A detailed listing of the loop conjugacy classes is presented. In particular, one of the loop conjugacy classes is shown to be properly contained in a superclass of the corresponding algebra group.
To everz partiallz ordered set a certain groupoid is assigned. A tolerance on it is defined similarlz as a congruence, onlz the requirement of transitivitz is omitted. Some theorems concerning these tolerances are proved.
In [Mwambene E., Multiples of left loops and vertex-transitive graphs, Cent. Eur. J. Math. 3 (2005), no. 2, 254–250] it was proved that every vertex-transitive graph is the Cayley graph of a left loop with respect to a quasi-associative Cayley set. We use this result to show that Cayley graphs of left loops with respect to such sets have some properties in common with Cayley graphs of groups which can be used to study a geometric theory for left loops in analogy to that for groups.
In this paper, by a travel groupoid is meant an ordered pair such that is a nonempty set and is a binary operation on satisfying the following two conditions for all : Let be a travel groupoid. It is easy to show that if , then if and only if . We say that is on a (finite or infinite) graph if and Clearly, every travel groupoid is on exactly one graph. In this paper, some properties of travel groupoids on graphs are studied.
The notion of travel groupoids was introduced by L. Nebeský in 2006 in connection with a study on geodetic graphs. A travel groupoid is a pair of a set and a binary operation on satisfying two axioms. We can associate a graph with a travel groupoid. We say that a graph has a travel groupoid if the graph associated with the travel groupoid is equal to . Nebeský gave a characterization of finite graphs having a travel groupoid. In this paper, we study travel groupoids on infinite graphs....
A characterization of all classes of idempotent groupoids having no more than two essentially binary term operations with respect to small finite models is given.