Search results for " MATHEMATICAL"
showing 10 items of 686 documents
Nonlinear Liouville Problems in a Quarter Plane
2016
We answer affirmatively the open problem proposed by Cabr\'e and Tan in their paper "Positive solutions of nonlinear problems involving the square root of the Laplacian" (see Adv. Math. {\bf 224} (2010), no. 5, 2052-2093).
Profit vs morality: how unfair is labor market discrimination? Results from a survey experiment
2019
Using an original survey-experimental protocol, we study the normative acceptability of the trade-off between immoral profit (discrimination) and costly morality (non-discrimination). We test the causal influence of three factors: i) the origin of discrimination, ii) the steepness of the morality/profit trade-off and iii) anti-discriminatory moral injunctions. Contrasting with past experimental and attitudinal studies, we find that a significant minority of respondents believe that labor market discrimination is acceptable when morality results in profit loss. We also find that the three tested factors have significant effects on normative opinions. Respondents are more likely to choose pro…
The development of Early Mathematical Skills – A Theoretical Framework for a Holistic Model
2019
This article presents a theoretical framework for a holistic model of the development of early mathematical skills in early childhood education. The first aim of this study was to conduct a comprehensive international review of the literature to explore early mathematical skills categories. The literature review yielded three early mathematical skills categories, namely (1) numerical skills, (2) spatial thinking skills and (3) mathematical thinking and reasoning skills. Previous studies have shown that several mathematical skills develop gradually and simultaneously in early ages and that these skills areas are interconnected in mathematical skills learning. Accordingly, the second aim of t…
Analysis of the determinants of entrepreneurial intention: the case of Burkina Faso
2018
International audience; In this study, we propose to analyze students' entrepreneurial intention, drawing on Lazear's (2004) self-selection model. This model captures the role of "human capital" in employment assignment and emphasizes the importance of the variety of skills in the individual's entrepreneurial orientation. For this purpose, we have a database collected in 2017 from over 1000 students at Ouaga I and Ouaga II universities in Burkina Faso. The results of estimates obtained using the quantile regression method show a positive and significant effect of the diversity of skills on the intention score, mainly at the median level. Even if the effect is not strong, this result support…
Topological canal foliations
2019
Regular canal surfaces of $\mathbb{R}^3$ or $\mathbb{S}^3$ admit foliations by circles: the characteristic circles of the envelope. In order to build a foliation of $\mathbb{S}^3$ with leaves being canal surfaces, one has to relax the condition “canal” a little (“weak canal condition”) in order to accept isolated umbilics. Here, we define a topological condition which generalizes this “weak canal” condition imposed on leaves, and classify the foliations of compact orientable 3-manifolds we can obtain this way.
Acoustic wave guides as infinite-dimensional dynamical systems
2015
We prove the unique solvability, passivity/conservativity and some regularity results of two mathematical models for acoustic wave propagation in curved, variable diameter tubular structures of finite length. The first of the models is the generalised Webster's model that includes dissipation and curvature of the 1D waveguide. The second model is the scattering passive, boundary controlled wave equation on 3D waveguides. The two models are treated in an unified fashion so that the results on the wave equation reduce to the corresponding results of approximating Webster's model at the limit of vanishing waveguide intersection.
Regularity and modulus of continuity of space-filling curves
2019
We study critical regularity assumptions on space-filling curves that possess certain modulus of continuity. The bounds we obtain are essentially sharp, as demonstrated by an example. peerReviewed
Introduction to Mathematical Logic, Edition 2021
2021
Textbook for students in mathematical logic. First order languages. Axioms of constructive and classical logic. Proving formulas in propositional and predicate logic. Glivenko's theorem and constructive embedding. Axiom independence. Interpretations, models and completeness theorems. Normal forms. Tableaux and resolution methods. Herbrand's theorem. Sections 1, 2, 3 represent an extended translation of the corresponding chapters of the book: V. Detlovs, Elements of Mathematical Logic, Riga, University of Latvia, 1964, 252 pp. (in Latvian).
Análisis de los antecedentes histórico-filosóficos de la "paradoja cognitiva de Duval"
2015
In a famous article published in 1993, Raymond Duval highlighted a simple fact: the student may confuse the mathematical object O he is trying to build cognitively with one of its semiotic representations R(O). Duval explained that this confusion was due to a sort of inevitable paradox: only someone who has already built O, can recognize R(O) as a representation of O and not as an object in itself. Thereafter, this thought has been extremely influential for researchers. However, even if in different terms, many scholars of semiotics have emphasized the same phenomenon. In this paper we propose to remind some of them. En un famoso artículo publicado en 1993, Raymond Duval evidenciaba el sigu…
Evaluation of biogas production and usage potential
2016
The aim of the research is the development of theoretical and methodical bases for determining the feasibility of plant raw materials growing for its further bioconversion into energy resources and tec hnological materials to maximize profit from business activities. Monograph, statistics, modelling and abstract logical methods have been used during the research. Directions of biogas usage have been examined. Biogas yields from different crops have been analyzed. It has been determined that high methane yields can be provided from root crops, grain crops, and several green forage plants. So, forage beet and maize can provide more than 5,500 m3 of biogas per hectare. Attention is paid to the…