Annotated translation of Parastrophic-orthogonal quasigroups, Acad. Nauk Moldav. SSR, Inst. Mat.s Vychisl. Tsentrom, Kishinev, 1983, prepared by A.D.Keedwell and P.Syrbu based on the original Russian and on an earlier English translation supplied to the rst author by Belousov himself. The notion of orthogonality plays an important role in the theory of Latin squares, and consequently also in th...

Latin squares of order n exist for each n ≥ 1. There are severalways of constructing Latin squares. Also for n≥ 2, if the number of reduced Latin squares isknown, then the number of general Latin squares canbecalculated. This paperproposed a generalmethod to constructsymmetric Latin squares of orderq by using blocks of order q which have the basic property of a recursivealgorithmwith the use of...

Let k ≥ 0 and n ≥ 2 be integers. A SOMA, or more specifically a SOMA(k, n), is an n×n array A, whose entries are k-subsets of a kn-set Ω, such that each element of Ω occurs exactly once in each row and exactly once in each column of A, and no 2-subset of Ω is contained in more than one entry of A. A SOMA(k, n) can be constructed by superposing k mutually orthogonal Latin squares of order n with...

Our main result essentially reduces the problem of finding an edge-decomposition of a balanced r-partite graph of large minimum degree into r-cliques to the problem of finding a fractional r-clique decomposition or an approximate one. Together with very recent results of Bowditch and Dukes as well as Montgomery on fractional decompositions into triangles and cliques respectively, this gives the...