Lars-Daniel Öhman

Avoiding Arrays of Odd Order by Latin Squares

We prove that there is a constant c such that, for each positive integer k, every (2k + 1) x (2k + 1) array A on the symbols 1, ... , 2k + 1 with at most c(2k + 1) symbols in every cell, and each s ...

Beauty as fit: a metaphor in mathematics?

Beauty, which plays a central role in the practice of mathematics, is almost absent in discussions of school mathematics. This is problematic, because students will decide whether or not to continu ...

Triple arrays and Youden squares

This paper addresses the question of when triple arrays can be constructed from Youden squares by removing a column together with the symbols therein, and then exchanging the role of columns and symbols. The scope of the investigation is limited to the standard case of triple arrays with

Simulation relations for pattern matching in directed graphs

v=r+c-1

Latin Squares with Forbidden Entries

v=r+c-1. For triple arrays with

A note on completing latin squares.

\lambda _{cc}=1