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Université de Fribourg

On the bend number of circular-arc graphs as edge intersection graphs of paths on a grid

Alcón, Liliana ; Bonomo, Flavia ; Durán, Guillermo ; Gutierrez, Marisa ; Mazzoleni, María Pía ; Ries, Bernard ; Valencia-Pabon, Mario

In: Discrete applied mathematics, 2018, vol. 234, p. 12-21

Golumbic, Lipshteyn and Stern [12] proved that every graph can be represented as the edge intersection graph of paths on a grid (EPG graph), i.e., one can associate with each vertex of the graph a nontrivial path on a rectangular grid such that two vertices are adjacent if and only if the corresponding paths share at least one edge of the grid. For a nonnegative integer k, Bk-EPG graphs are...

Public access from 11-ott-2020
Université de Fribourg

Critical vertices and edges in H-free graphs

Paulusma, Daniël ; Picouleau, Christophe ; Ries, Bernard

In: Discrete applied mathematics, 2019, vol. 257, p. 361-367

A vertex or edge in a graph is critical if its deletion reduces the chromatic number of the graph by one. We consider the problems of deciding whether a graph has a critical vertex or edge, respectively. We give a complexity dichotomy for both problems restricted to H-free graphs, that is, graphs with no induced subgraph isomorphic to H. Moreover, we show that an edge is critical if and only...

Université de Fribourg

Intra and extracellular journey of the phytohormone salicylic acid

Maruri-López, Israel ; Aviles-Baltazar, Norma Yaniri ; Buchala, Antony J. ; Serrano, Mario

In: Frontiers in Plant Science, 2019, vol. 10, p. -

Salicylic acid (SA) is a plant hormone that has been described to play an essential role in the activation and regulation of multiple responses to biotic and to abiotic stresses. In particular, during plant-microbe interactions, as part of the defense mechanisms, SA is initially accumulated at the local infected tissue and then spread all over the plant to induce systemic acquired resistance...

Université de Fribourg

On the minimum and maximum selective graph coloring problems in some graph classes

Ries, Bernard

In: Discrete Applied Mathematics, 2016, vol. 204, p. 77-89

Given a graph together with a partition of its vertex set, the minimum selective coloring problem consists of selecting one vertex per partition set such that the chromatic number of the subgraph induced by the selected vertices is minimum. The contribution of this paper is twofold. First, we investigate the complexity status of the minimum selective coloring problem in some specific graph...

Université de Fribourg

Institutional effects on nurses’ working conditions: a multi-group comparison of public and private non-profit and for-profit healthcare employers in Switzerland

Aeschbacher, Remo ; Addor, Véronique

In: Human Resources for Health, 2018, vol. 16, no. 58, p. 1-10

Background: In response to the need for competitive recruitment of nurses resulting from the worldwide nursing shortage, employers need to attract and retain nurses by promoting their competitive strengths in their working conditions (WCS) and by addressing their competitive weaknesses. This study investigated workplace differences between public hospitals (PuHs), private for-profit hospitals...

Université de Fribourg

Comparative Law and Human Rights

Besson, Samantha

In: The Oxford Handbook of Comparative Law, 2nd ed., 2019, p. 1222-1249

Université de Fribourg

Article 2. The Right to Non-Discrimination

Besson, Samantha ; Kleber, Eleonor

In: The UN Convention on the Rights of the Child - A Commentary, 2019, p. 41-72

Université de Fribourg

Do Anti-Corruption Educational Campaigns Reach Students? : Evidence from Russia and Ukraine

Denisova-Schmidt, Elena ; Huber, Martin ; Leontyeva, Elvira

In: Educational studies. Moscow, 2016, no. 1, p. 61-83

The authors investigate the effect of anti-corruption educational materials — an informational folder with materials designed by Transparency International — on the willingness of students to participate in an anti-corruption campaign and their general judgment about corruption in two cities in Russia and Ukraine by conducting experiments. During a survey of 350 students in Khabarovsk,...

Public access from 20-feb-2021
Université de Fribourg

Classifying k-edge colouring for H-free graphs

Galby, Esther ; T. Lima, Paloma ; Paulusma, Daniël ; Ries, Bernard

In: Information procesing letters, 2019, vol. 146, p. 39-43

A graph is H-free if it does not contain an induced subgraph isomorphic to H. For every integer k and every graph H, we determine the computational complexity of k-Edge Colouring for H-free graphs.