Overlapping latin subsquares and full products

Joshua M. Browning; Petr Vojtěchovský; Ian M. Wanless

Displaying similar documents to “Overlapping latin subsquares and full products”

Constructing and embedding mutually orthogonal Latin squares: reviewing both new and existing results

Diane M. Donovan, Mike Grannell, Emine Ş. Yazıcı (2020)

Commentationes Mathematicae Universitatis Carolinae

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We review results for the embedding of orthogonal partial Latin squares in orthogonal Latin squares, comparing and contrasting these with results for embedding partial Latin squares in Latin squares. We also present a new construction that uses the existence of a set of $t$ mutually orthogonal Latin squares of order $n$ to construct a set of $2 t$ mutually orthogonal Latin squares of order $n^{t}$ .

Equivalence classes of Latin squares and nets in ${ℂ P}^{2}$

Corey Dunn, Matthew Miller, Max Wakefield, Sebastian Zwicknagl (2014)

Annales de la faculté des sciences de Toulouse Mathématiques

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The fundamental combinatorial structure of a net in $ℂ P^{2}$ is its associated set of mutually orthogonal Latin squares. We define equivalence classes of sets of orthogonal Latin squares by label equivalences of the lines of the corresponding net in $ℂ P^{2}$ . Then we count these equivalence classes for small cases. Finally we prove that the realization spaces of these classes in $ℂ P^{2}$ are empty to show some non-existence results for 4-nets in $ℂ P^{2}$ .

On orthogonal Latin $p$ -dimensional cubes

Marián Trenkler (2005)

Czechoslovak Mathematical Journal

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We give a construction of $p$ orthogonal Latin $p$ -dimensional cubes (or Latin hypercubes) of order $n$ for every natural number $n \neq 2, 6$ and $p \geq 2$ . Our result generalizes the well known result about orthogonal Latin squares published in 1960 by R. C. Bose, S. S. Shikhande and E. T. Parker.

Solvability classes for core problems in matrix total least squares minimization

Iveta Hnětynková, Martin Plešinger, Jana Žáková (2019)

Applications of Mathematics

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Linear matrix approximation problems $A X \approx B$ are often solved by the total least squares minimization (TLS). Unfortunately, the TLS solution may not exist in general. The so-called core problem theory brought an insight into this effect. Moreover, it simplified the solvability analysis if $B$ is of column rank one by extracting a core problem having always a unique TLS solution. However, if the rank of $B$ is larger, the core problem may stay unsolvable in the TLS sense, as shown for the first...

On Sums of Squares in $Q^{\frac{1}{2}} (X)$ etc

W. J. Ellison (1970-1971)

Séminaire de théorie des nombres de Bordeaux

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Normality, nuclear squares and Osborn identities

Aleš Drápal, Michael Kinyon (2020)

Commentationes Mathematicae Universitatis Carolinae

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Let $Q$ be a loop. If $S \leq Q$ is such that $ϕ (S) \subseteq S$ for each standard generator of Inn $Q$ , then $S$ does not have to be a normal subloop. In an LC loop the left and middle nucleus coincide and form a normal subloop. The identities of Osborn loops are obtained by applying the idea of nuclear identification, and various connections of Osborn loops to Moufang and CC loops are discussed. Every Osborn loop possesses a normal nucleus, and this nucleus coincides with the left, the right and the middle nucleus....

Exceptional sets in Waring's problem: two squares and s biquadrates

Lilu Zhao (2014)

Acta Arithmetica

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Let $R_{s} (n)$ denote the number of representations of the positive number n as the sum of two squares and s biquadrates. When $s = 3$ or 4, it is established that the anticipated asymptotic formula for $R_{s} (n)$ holds for all $n \leq X$ with at most $O (X^{(9 - 2 s) / 8 + ε})$ exceptions.

Nonassociative triples in involutory loops and in loops of small order

Aleš Drápal, Jan Hora (2020)

Commentationes Mathematicae Universitatis Carolinae

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A loop of order $n$ possesses at least $3 n^{2} - 3 n + 1$ associative triples. However, no loop of order $n > 1$ that achieves this bound seems to be known. If the loop is involutory, then it possesses at least $3 n^{2} - 2 n$ associative triples. Involutory loops with $3 n^{2} - 2 n$ associative triples can be obtained by prolongation of certain maximally nonassociative quasigroups whenever $n - 1$ is a prime greater than or equal to $13$ or $n - 1 = p^{2 k}$ , $p$ an odd prime. For orders $n \leq 9$ the minimum number of associative triples is reported for both general...

The number of squares and $B_{h} [g]$ sets

Ben Green (2001)

Acta Arithmetica

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Automorphic loops and metabelian groups

Mark Greer, Lee Raney (2020)

Commentationes Mathematicae Universitatis Carolinae

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Given a uniquely 2-divisible group $G$ , we study a commutative loop $(G, \circ)$ which arises as a result of a construction in “Engelsche elemente noetherscher gruppen” (1957) by R. Baer. We investigate some general properties and applications of “ $\circ$ ” and determine a necessary and sufficient condition on $G$ in order for $(G, \circ)$ to be Moufang. In “A class of loops categorically isomorphic to Bruck loops of odd order” (2014) by M. Greer, it is conjectured that $G$ is metabelian if and only if $(G, \circ)$ is an automorphic...