We define a k-plex to be a partial latin square of order n containing kn entries such that exactly k entries lie in each row and column and each of n symbols occurs exactly k times. A transversal of a latin square corresponds to the case k = 1. For k > n/4 we prove that not all k-plexes are completable to latin squares. Certain latin squares, including the Cayley tables of many groups, are show...

Background: The choices of experimental design as well as of statistical analysis are of huge importance in field experiments. These are necessary to be correctly in order to obtain the best possible precision of the results. The random arrangements, randomized blocks and Latin square designs were reviewed and analyzed from the statistical perspective of error analysis. Material and Method: Ran...

The parity vectors of two Latin squares of the same side n provide a necessary condition for the two squares to be biembeddable in an orientable surface. We investigate constraints on the parity vector of a Latin square resulting from structural properties of the square, and show how the parity vector of a direct product may be obtained from the parity vectors of the constituent factors. Parity...

Cheating on standardized tests has been a major concern as it potentially minimizes measurement precision. One major way to reduce cheating by collusion is to administer multiple forms of a test. Even with this approach, potential collusion is still quite large. A Latin-square treatment structure for distributing multiple forms is proposed to further reduce the colluding potential. An index to ...

Growing meat goats of 4 types (Boer and Spanish of both wethers and doelings) were used to evaluate conditions for a method of testing efficacy of electric-fence strand additions to barbed-wire fence used for cattle to also contain goats. Animals were allocated to 8 sets, with each set consisting of 5 groups. There was 1 goat of each of the 4 types in a group. One side of five 2.4- × 3.7-m eval...

A 1-factorization of a graph is a decomposition of the graph into edge disjoint perfect matchings. There is a well-known method, which we call the K-construction, for building a 1-factorization of Kn;n from a 1-factorization of Knþ1. The 1-factorization of Kn;n can be written as a latin square of order n. The K-construction has been used, among other things, to make perfect 1-factorizations, su...

The parity type of a Latin square is defined in terms of the numbers of even and odd rows and columns. It is related to an Alon-Tarsi-like conjecture that applies to Latin squares of odd order. Parity types are used to derive upper bounds for the size of autotopy groups. A new algorithm for finding the autotopy group of a Latin square, based on the cycle decomposition of its rows, is presented,...

A k-plex in a latin square of order n is a selection of kn entries that includes k representatives from each row and column and k occurrences of each symbol. A 1-plex is also known as a transversal. It is well known that if n is even then Bn, the addition table for the integers modulo n, possesses no transversals. We show that there are a great many latin squares that are similar to Bn and have...

For every odd positive integer m we prove the existence of a Latin square of order 3m having no proper Latin subsquares. Combining this with previously known results it follows that subsquare-free Latin squares exist for all odd orders. © 2005 Elsevier Ltd. All rights reserved.