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On-line Covering the Unit Square with Squares

Janusz Januszewski (2009)

Bulletin of the Polish Academy of Sciences. Mathematics

The unit square can be on-line covered with any sequence of squares whose total area is not smaller than 4.

On-line Packing Squares into n Unit Squares

Janusz Januszewski (2010)

Bulletin of the Polish Academy of Sciences. Mathematics

If n ≥ 3, then any sequence of squares of side lengths not greater than 1 whose total area does not exceed ¼(n+1) can be on-line packed into n unit squares.

Optimisation hybride par colonies de fourmis pour le problème de découpe à deux dimensions

Alice Yalaoui, Chengbin Chu (2009)

RAIRO - Operations Research

Nous nous intéressons dans cet article au problème de découpe guillotine en deux dimensions noté 2BP/O/G. Il s'agit de découper un certain nombre de pièces rectangulaires dans un ensemble de plaques de matière première, elles même rectangulaires et identiques. Celles-ci sont disponibles en quantité illimitée. L'objectif est de minimiser le nombre de plaques utilisées pour satisfaire la demande, en appliquant une succession de coupes, dites guillotines, allant de bout en bout. Nous proposons une approche...

Orthogonal double covers of complete graphs by fat caterpillars

Dalibor Froncek, Uwe Leck (2006)

Discussiones Mathematicae Graph Theory

An orthogonal double cover (ODC) of the complete graph Kₙ by some graph G is a collection of n spanning subgraphs of Kₙ, all isomorphic to G, such that any two of the subgraphs share exactly one edge and every edge of Kₙ is contained in exactly two of the subgraphs. A necessary condition for such an ODC to exist is that G has exactly n-1 edges. We show that for any given positive integer d, almost all caterpillars of diameter d admit an ODC of the corresponding complete graph.

Packings of pairs with a minimum known number of quadruples

Jiří Novák (1995)

Mathematica Bohemica

Let E be an n -set. The problem of packing of pairs on E with a minimum number of quadruples on E is settled for n < 15 and also for n = 36 t + i , i = 3 , 6 , 9 , 12 , where t is any positive integer. In the other cases of n methods have been presented for constructing the packings having a minimum known number of quadruples.

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