17 research outputs found
Coloring Points with Respect to Squares
No full textWe consider the problem of 2-coloring geometric hypergraphs. Specifically, we show that there is a constant m such that any finite set S of points in the plane can be 2-colored such that every axis-parallel square that contains at least m points from S contains points of both colors. Our proof is constructive, that is, it provides a polynomial-time algorithm for obtaining such a 2-coloring. By affine transformations this result immediately applies also when considering homothets of a fixed parallelogram
Generalized Turan problems for disjoint copies of graphs
No full textGiven two graphs H and F, the maximum possible number of copies of H in an F-free graph on n vertices is denoted by ex(n, H, F). We investigate the function ex(n, H, kF), where kF denotes k vertex disjoint copies of a fixed graph F. Our results include cases when F is a complete graph, cycle or a complete bipartite graph. (C) 2019 Elsevier B.V. All rights reserved.DC
Asyrnptotics for the Turan number of Berge-K-2,K-t
No full textLet F be a graph. A hypergraph is called Berge-F if it can be obtained by replacing each edge in F by a hyperedge containing it.Let F be a family of graphs. The Turan number of the family Berge-F is the maximum possible number of edges in an r-uniform hypergraph on n vertices containing no Berge-F as a subhypergraph (for every F is an element of F) and is denoted by ex(r)(n, F).We determine the asymptotics for the Turan number of Berge-K-2,K-t, by showingex(3)(n, K-2,K-t) = (1 + o(1))1/6 (t - 1)(3/2) . n(3/2)for any given t >= 7. We study the analogous question for linear hypergraphs and showex(3)(n,{C-2, K-2,K-t}) = (1 + o(t)(1))1/6 root t - 1. n(3/2).We also prove general upper and lower bounds on the Turan numbers of a class of graphs including ex(r)(n, K-2,K-t), ex(r)(n, {C-2, K-2,K-t}), and ex,(n, C-2k) for r >= 3. Our bounds improve the results of Gerbner and Palmer [18], Fiiredi and Ozkahya [15], Timmons [37], and provide a new proof of a result of Jiang and Ma [26]. (C) 2019 Elsevier Inc. All rights reserved.DC
Modelagem do conhecimento social
No full textThis article presents a summary of the theoretical proposals strategies that the author has developed over the last few years, and are in the book "The visible (in) plot of social life: Communication, meaning and reality "(La Crujía, Bs. As. 2003/06). The objective here is to present hypotheses and proposals for categories of analysis that enable the construction of a Research Program Socio-communicational, taking as reference the Propositions of Imre Lakatos (PIC). The author considers that these can serve as an ideal reference in construction of some conceptual keys that help to base and demarcate themes or problems the field of communication in order to design a possible analytical "reference map" for the development of articulated investigations, and aimed at a systematization of the field Communicational (or socio-communicational).Este paper presenta un resúmen de propuestas teóricas y estrategias que el autor ha venido desarrollando en los últimos años, sobre todo en “La trama (in)visible de la vida social: comunicación, sentido y realidad”. El objetivo es presentar hipótesis y categorías de análisis tentativas que aporten a la construcción de un Programa de Investigación socio-comunicacional tomando como referencia ideal las proposiciones de Lakatos (PIC). El autor considera que las proposiciones que presenta ayudan a asumir ciertas claves conceptuales para fundamentar, demarcar temáticas y problemáticas centrales del campo, a fin de diseñar un posible “mapa de referencia” analítica para el desarrollo de investigaciones articuladas hacia una sistematización del campo comunicacional (o sociocomunicacional).Este artigo apresenta um resumo das propostas teóricas e estratégicas que o autor vem desenvolvendo ao longo dos últimos anos, e que sobretudo aparecem no livro “La trama (in)visible de la vida social: comunicación, sentido y realidad” (La Crujía, Bs. As. 2003/06). O objetivo aqui é apresentar hipóteses e propostas de categorias de análises que possibilitem a construção de um Programa de Investigação sócio-comunicacional, tomando como referência as proposições de Imre Lakatos (PIC). O autor considera que estas podem servir como referência ideal na construção de algumas chaves conceituais que ajudem a fundamentar e demarcar temáticas ou problemáticas centrais do campo da comunicação, a fim de desenhar um possível “mapa de referência” analítico para o desenvolvimento de investigações articuladas, e voltadas a uma sistematização do campo comunicacional (ou sócio-comunicacional)
On the size of planarly connected crossing graphs
No full textWe prove that if an n-vertex graph G can be drawn in the plane such that each pair of crossing edges is independent and there is a crossing-free edge that connects their endpoints, then G has O(n) edges. Graphs that admit such drawings are related to quasi-planar graphs and to maximal 1-planar and fan-planar graphs
On clique coverings of complete multipartite graphs
No full textA clique covering of a graph G is a set of cliques of G such that any edge of G is contained in one of these cliques, and the weight of a clique covering is the sum of the sizes of the cliques in it. The sigma clique cover number scc(G) of a graph G, is defined as the smallest possible weight of a clique covering of G.Let K-t(d) denote the complete t-partite graph with each part of size d. We prove that for any fixed d >= 2, we havelim(t ->infinity) scc(K-t(d)) = d/2t log t.This disproves a conjecture of Davoodi et al. (2016). (C) 2019 Elsevier B.V. All rights reserved.DC
Cambrian detrital zircon signatures of the northern Canadian Cordilleran passive margin, Liard area, Canada: evidence of sediment recycling, non-Laurentian ultimate sources and basement denudation.
No full textDetrital zircon U-Pb age probability distributions for the Cambrian Vizer formation (informal) and Mount Roosevelt Formation (middle member) of the northern Canadian Cordilleran passive margin indicate extensive recycling from ~1.7 to 1.6 Ga Paleoproterozoic sandstones and Proterozoic and Lower Cambrian strata, respectively. The units have minor or no first cycle input from Laurentian basement. The lower part of the Vizer formation contains North American Magmatic Gap (1610 to1490 Ma) detrital zircons and lacks ultimate Grenvillian sourced grains, indicating that the grains were likely sourced from a nearby Mesoproterozoic basin and have an ultimate non-Laurentian source. Detrital zircon U-Pb ages of 670 to 640 Ma from the middle member of the Mount Roosevelt Formation indicate associated volcanic clasts were locally sourced, and are not of syn-sedimentary Middle Cambrian age. Provenance of these units was indirectly impacted by the Liard Line basement feature.
Detrital zircon U-Pb age probability distributions from the northern Canadian Cordilleran passive margin indicate sediments were sourced from the east in the Early Cambrian (Terreneuvian; Vizer formation and correlatives) and the northeast during Early Cambrian (Series 2) deposition of Sekwi Formation and correlative strata. In the early Middle Cambrian the middle member of the Mount Roosevelt Formation was primarily locally sourced, whereas the upper member was derived from Laurentian basement to the east and southeast. The change from reworked Paleoproterozoic cover in the Terrenuvian to primary basement sources in the Middle Cambrian suggests significant denudation of the basement occurred southeast of the Liard Line.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
Modelagem do conhecimento social
No full textThis article presents a summary of the theoretical proposals strategies that the author has developed over the last few years, and are in the book "The visible (in) plot of social life: Communication, meaning and reality "(La Crujía, Bs. As. 2003/06). The objective here is to present hypotheses and proposals for categories of analysis that enable the construction of a Research Program Socio-communicational, taking as reference the Propositions of Imre Lakatos (PIC). The author considers that these can serve as an ideal reference in construction of some conceptual keys that help to base and demarcate themes or problems the field of communication in order to design a possible analytical "reference map" for the development of articulated investigations, and aimed at a systematization of the field Communicational (or socio-communicational).Este paper presenta un resúmen de propuestas teóricas y estrategias que el autor ha venido desarrollando en los últimos años, sobre todo en “La trama (in)visible de la vida social: comunicación, sentido y realidad”. El objetivo es presentar hipótesis y categorías de análisis tentativas que aporten a la construcción de un Programa de Investigación socio-comunicacional tomando como referencia ideal las proposiciones de Lakatos (PIC). El autor considera que las proposiciones que presenta ayudan a asumir ciertas claves conceptuales para fundamentar, demarcar temáticas y problemáticas centrales del campo, a fin de diseñar un posible “mapa de referencia” analítica para el desarrollo de investigaciones articuladas hacia una sistematización del campo comunicacional (o sociocomunicacional).Este artigo apresenta um resumo das propostas teóricas e estratégicas que o autor vem desenvolvendo ao longo dos últimos anos, e que sobretudo aparecem no livro “La trama (in)visible de la vida social: comunicación, sentido y realidad” (La Crujía, Bs. As. 2003/06). O objetivo aqui é apresentar hipóteses e propostas de categorias de análises que possibilitem a construção de um Programa de Investigação sócio-comunicacional, tomando como referência as proposições de Imre Lakatos (PIC). O autor considera que estas podem servir como referência ideal na construção de algumas chaves conceituais que ajudem a fundamentar e demarcar temáticas ou problemáticas centrais do campo da comunicação, a fim de desenhar um possível “mapa de referência” analítico para o desenvolvimento de investigações articuladas, e voltadas a uma sistematização do campo comunicacional (ou sócio-comunicacional)
Análisis del discurso del graffiti, y su representación en la novela “Edén y Eva” del escritor ecuatoriano, Huilo Ruales Hualca.
No full textEste estudio identifica, mediante el análisis de los elementos discursivos y su correlación con la narrativa y la comunicación, cómo está representado el graffiti en la novela “Edén y Eva” del escritor ecuatoriano Huilo Ruales. Para efectuar la investigación, se consultó los trabajos desarrollados por: Michel Foucault, Paul Ricoeur, Henri Lefèvre, Stuart Hall, Jesús Martín Barbero, Eduardo Vizer, Umberto Eco y Mieke Bal; aportes teóricos que fueron relevantes para comprender y establecer relaciones entre el discurso representado mediante el lenguaje narrativo y las percepciones tanto del autor de la novela, Huilo Ruales, como la de un graffitero de la ciudad de Quito. El trabajo se divide en tres capítulos: discurso y representación, comunicación y narrativa, y el estudio de caso de la novela. Se concluye que el discurso del graffitero tiene relación con la realidad circundante, así como con los contextos de producción e interpretación que se encuentran en los procesos de comunicación.This study identifies, by means of analysis of discursive elements and its correlation with narrative and communication, how graffiti is represented in Eden and Eve, novel by Ecuadorian writer Huilo Ruales. In order to make this investigation, we looked up the works developed by: Michel Foucault, Paul Ricoeur, Henri Lefèbvre, Stuart Hall, Jesús Martín Barbero, Eduardo Vizer, Umberto Eco and Mieke Bal; whose theoretic contributions are relevant to understand and to establish relations between the speech represented by means of narrative language and the novel author perceptions as much as of, Huilo Ruales, as one of the city of Quito graffiti painters. This work splits into three chapters: speech and representation, communication and narrative, and the novel study. I concluded that the graffiti speech is related to the surrounding reality, as well as with production and interpretation contexts found in communication processes
