Book contents
- Frontmatter
- Contents
- PREFACE
- GRAPHS AND INTERCONNECTION NETWORKS: DIAMETER AND VULNERABILITY
- THE FRIENDSHIP THEOREM AND THE LOVE PROBLEM
- MAXIMUM SETS IN FINITE PROJECTIVE SPACES
- QUASIGROUP IDENTITIES AND ORTHOGONAL ARRAYS
- BOUNDS ON PERMANENTS, AND THE NUMBER OF 1-FACTORS AND 1-FACTORIZATIONS OF BIPARTITE GRAPHS
- REDFIELD DISCOVERED AGAIN
- CHARACTERIZATIONS OF THE LIE INCIDENCE GEOMETRIES
- GL(n, C) FOR COMBINATORIALISTS
- IRREGULARITIES OF PARTITIONS: RAMSEY THEORY, UNIFORM DISTRIBUTION
- INDEX OF NAMES
- SUBJECT INDEX
QUASIGROUP IDENTITIES AND ORTHOGONAL ARRAYS
Published online by Cambridge University Press: 05 May 2013
- Frontmatter
- Contents
- PREFACE
- GRAPHS AND INTERCONNECTION NETWORKS: DIAMETER AND VULNERABILITY
- THE FRIENDSHIP THEOREM AND THE LOVE PROBLEM
- MAXIMUM SETS IN FINITE PROJECTIVE SPACES
- QUASIGROUP IDENTITIES AND ORTHOGONAL ARRAYS
- BOUNDS ON PERMANENTS, AND THE NUMBER OF 1-FACTORS AND 1-FACTORIZATIONS OF BIPARTITE GRAPHS
- REDFIELD DISCOVERED AGAIN
- CHARACTERIZATIONS OF THE LIE INCIDENCE GEOMETRIES
- GL(n, C) FOR COMBINATORIALISTS
- IRREGULARITIES OF PARTITIONS: RAMSEY THEORY, UNIFORM DISTRIBUTION
- INDEX OF NAMES
- SUBJECT INDEX
Summary
Introduction. Let (Q,o) be a quasigroup of order n and define an n2 × 3 array A by (x,y,z) is a row of A if and only if x o y = z. As a consequence of the fact that the equations a o x = b and y o a = b are uniquely solvable for all a,b ε Q, if we run our fingers down any two columns of A we get each ordered pair belonging to Q × Q e×actly once. An n2 × 3 array with this property is called an orthogonal array and it doesn't take the wisdom of a saint to see that this construction can be reversed. That is, if A is any n2 × 3 orthogonal array (defined on a set Q) and we define a binary operation o on Q by x o y = z if and only if (x,y,z) is a row of A, then (Q,o) is a quasigroup. Hence we can think of a quasigroup as an n2 × 3 orthogonal array and conversely. Now given an n2 × 3 orthogonal array A there is the irresistable urge to permute the columns of A. One of the reasons for this urge is that the resulting n2 × 3 array is still an orthogonal array. (If running our fingers down any two columns of A gives every ordered pair of Q × Q exactly once, the same must be true (of course) if we rearrange the columns.)
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- Surveys in CombinatoricsInvited Papers for the Ninth British Combinatorial Conference 1983, pp. 77 - 106Publisher: Cambridge University PressPrint publication year: 1983
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