Ricerche in Didattica della Matematica e in Matematiche Elementari
Riemann solution for hyperbolic equations with discontinuous coefficients
This paper deals with a Riemann solution for scalar hyperbolic equations with discontinuous coefficients. In many numerical schemes of Godunov type in fluid dynamics, electromagnetic and so on, usually hyperbolic problems are solved to estimate fluxes. The exact solution is generally difficult to obtain, but good approximations are provided in many situations like Roe and HLLC Riemann solvers in fluid. However all these solvers assumes that the acoustic waves speeds are continuous which is not...
Rozhovor s Michaelem Atiyahem
Rozvodová pře
Rudinovy učebnice matematické analýzy
RusDML 2008
The purpose of this extended abstract is to summarize the report on the final achievements of the RusDML project, where this acronym stands for Russian Digital Mathematical Library. The initial phases of the project have been described in [Evstigneeva, G. A., Wegner, B.: O proekte sozdanija elektronnogo archiva russkich publikatsii po matematiki. Proceedings of LIBCOM 2002, Yershovo, November 2002.] and [Evstigneeva, G. A., Zemskov, A.: RusDML — a Russian-German project for establishing a digital...
Šachové úlohy v kombinatorice
Článek pojednává o matematických úlohách souvisejících se šachovnicí a šachovými figurami. Ze šachu však budeme potřebovat pouze pravidla pro pohyb figur po šachovnici. Postupně se zaměřujeme na jezdcovy procházky po obdélníkových šachovnicích a dále na tzv. nezávislost a dominanci figur a vztah mezi nimi na čtvercových šachovnicích. Ukážeme, že některé problémy lze řešit elegantněji, pokud je přeformulujeme v řeči teorie grafů.
Savoir manier les instruments : la géométrie dans les écrits italiens d’architecture (1545-1570)
Cet article est consacré à la géométrie véhiculée par les écrits d’architecture, en particulier les écrits italiens de la seconde moité du xvie siècle. Il explore le rôle central attribué aux instruments dans cette géométrie. De quelle façon s’insère-t-elle dans les multiples traditions mathématiques de la même époque ? Elle se nourrit de fait à la fois d’apports de la tradition savante, de celle des abacistes et de la géométrie pratique. On s’attachera à mettre en évidence, dans les propositions...
Selected Chapters From Algebra, I
Selected Chapters from Algebra, II
Selected Chapters from Algebra, III/1
Setkání s profesorem Gustavem Choquetem
Shoaling of nonlinear steady waves: maximum height and angle of breaking
A Fourier approximation method is used for modeling and simulation of fully nonlinear steady waves. The set of resulting nonlinear equations are solved by Newton's method. The shoaling of waves is simulated based on comparisons with experimental data. The wave heights and the angles of breaking are analysed until the limit of inadequacy of the numerical method. The results appear quite close to those criteria predicted by the theory of completely nonlinear surface waves and contribute to provide...
Sledování nemódních cílů
Small Scale Retrodigitization
The digitization of papers born in the print-only era is vital for the health of the mathematical record. Many large scale retrodigitization projects are underway and, at this point, probably more that half of the mathematical history has been finished. Many smaller journals and books remain to be done. This paper gives a framework within which these may also be completed. It uses the digitization of the Canadian Journal of Mathematics (53,000 pages), completed as a one-man project over a few months,...
Smooth approximation and its application to some 1D problems
In the contribution, we are concerned with the exact interpolation of the data at nodes given and also with the smoothness of the interpolating curve and its derivatives. This task is called the problem of smooth approximation of data. The interpolating curve or surface is defined as the solution of a variational problem with constraints. We discuss the proper choice of basis systems for this way of approximation and present the results of several 1D numerical examples that show the quality of smooth...
Solutions of hypersingular integral equations over circular domains by a spectral method
The problem of a solving a class of hypersingular integral equations over the boundary of a nonplanar disc is considered. The solution is obtained by an expansion in basis functions that are orthogonal over the unit disc. A Fourier series in the azimuthal angle, with the Fourier coefficients expanded in terms of Gegenbauer polynomials is employed. These integral equations appear in the study of the interaction of water waves with submerged thin plates.
Solving Equations, an Elegant Legacy
Some additive and multiplicative problem sin number theory
Some comments on the diversity of Vermeer paintings depicted on postage stamps
We present some comments on the diversity of the paintings by Johannes Vermeer (1632-1675) depicted on postage stamps. We have found 20 of the 36 "recognized" Vermeer paintings depicted on postage stamps issued by 29 "countries"; by country we mean here a stamp-issuing region that issues or has issued its own postage stamps. We apply Fisher's α index of biodiversity [11] to compare the diversity of Vermeer paintings depicted on postage stamps with the diversity of two other data sets [26]. We illustrate...