594 research outputs found
A fejszámoló Bolyai Farkas: Farkas Bolyai as a Mental Calculator / Farkas Bolyai și calculul mintal
No full textIn his childhood, the Hungarian mathematician, Farkas Bolyai (1775–1856) was a very good mental calculator. He calculated the square and cube roots of 14-digit numbers without pen and paper. In his legacy we found an interesting, but a little bit mysterious manuscript on the cube roots. Fortunately, we understood this paper based on a Hungarian arithmetical book by Lőrincz Koretz (1805–1871). The author of this book was a piarist teacher in Hungary. This paper shows some examples based on the unknown József Farczádi Nagy’s calculations of the cube roots.
Rezumat
În copilărie, matematicianul maghiar Farkas Bolyai (1775–1856) a fost capabil să extragă rădăcini pătrate și cubice din numere de 14 cifre. În moștenirea sa am găsit un manuscris interesant, deși puțin misterios, despre extragerea cubică. Din fericire, descifrarea conținutului s-a reușit pe baza unei cărți de matematică a lui Lőrinc Koretz (1805–1871). Autorul acestui volum a fost un profesor piarist. Prezentul articol dicută câteva exemple bazate pe calculele necunoscute ale lui József Farczádi Nagy ale rădăcinilor cubului.
Kivonat
Bolyai Farkas (1775–1856) már gyermekkorában 14 jegyű számból is tudott fejben négyzet- és köbgyököt vonni. Hagyatékában egy érdekes, bár egy kicsit titokzatos kéziratot találtunk, amely a köbgyökvonásról szól. Szerencsére sikerült megfejtetni a tartalmát Koretz Lőrincz (1805–1871) egy számtankönyve alapján. E kötet szerzője kegyesrendi tanár volt. Dolgozatunk néhány példát mutat be Farczádi Nagy József köbgyökvonási módszeréről
Csokonai könyvtár. Források (Régi kortársaink)
No full textA múlt század második felében a Bolyaiak iránti érdeklődést Bolyai Jánosnak
némileg megkésett, külföldi felfedezése indította el. Ez a figyelem irányította
rá a vizsgálódásokat a Bolyaiak matematikai teljesítményének
értékelésére, hagyatékuk feltárására és kutatására. A publikációk viszonylag
nagy száma természetszerűleg erre helyezi a hangsúlyt Bolyai Farkas esetében
is - torzóban maradt szépírói pályája folytán - indokoltan. Irodalmi
tevékenységéről csak mellékesen, az életpálya különössége és a szerteágazó
tehetség megnyilvánulásának illusztrálásaként emlékeztek meg. A drámákat
és egy fordításkötetet közreadó Bolyai Farkast az irodalomtörténetírás
számon tartotta, de irodalmi tevékenységének nem tulajdonítottak
különösebb értéket, inkább csak a nagy matematikus iránti tisztelet hangján
szóltak róla.
Bolyai drámai kísérleteinek jelentősége csak az 1810-cs évek drámairodalmának
a történeti feldolgozása során nyerte el méltó helyét, elsősorban Rohonyi Zoltán (Rohonyi 1975) és Nagy Imre (Nagy 1993) munkáival.
Bolyai Farkas drámái - minden dramaturgiai hiányosságuk ellenére - fontos
szerepet foglalnak el abban az alakulástörténetben, amely a magyar dráma
kulturális szerepfelfogásának megcrősödését,és a magyar nyelvű irodalom
hagyományrendjének kiteljesedését jelenti.Öt Szomoru Játék - 7-182.
Édes Hazám! - 9-10.; Pausániás vagy A' nagyravágyás' áldozatja - 11-44.; II. Mohamed vagy A' ditsöség' győzedelme a' szerelmen - 45-78.; Kemény Simon vagy A' hazaszeretet áldozatja - 79-106.;
A' virtus' győzedelme a' szerelmen - 107-142.; A' szerelem' győzedelme a' virtuson - 143-174.; Hibák és Igazitások - 175-179.; Némely Jegyzések - 180-182.
A' pári'si per - 183-264.; Kegyes Olvasó! 185-187.; A' pári'si per - 188-262.; Jegyzet - 263-264.; Függelék - 265; Jelentés - 265.;
Bolyai Farkas szellemi arcképéhez - 269-290.;
Jegyzetek - 291-344.; Általános megjegyzések - 291-317.; Jegyzetek az egyes munkákhoz - 318-344
Primal and Dual Characterizations for Farkas Type Lemmas in Terms of Closedness Criteria
No full textThis paper deals with the characterization, in terms of closedness of certain sets regarding other sets, of Farkas lemmas determining when the upperlevel set of a convex function f contains a set of the form C ∩ −1 (D), where C and D are convex sets (not necessarily cones) in locally convex spaces X (with topological dual X′) and Y, respectively, while is a continuous linear operator from X to Y. More in detail, each of the mentioned characterizations of Farkas type lemmas consists in the closedness of certain subset of either one of the “primal” spaces X × Y × ℝ and Y × ℝ, or of the “dual” space X′ × ℝ, regarding some singleton set of the corresponding space. Moreover, the paper also provides an existence theorem for the feasible set C ∩ −1 (D) in terms of the closedness of certain subset of the dual space X′ ×ℝ regarding the singleton set formed by the null element. These results are illustrated with significant applications to constrained convex minimization problems and to functional approximation by polynomials.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. The research of the first author has been partly supported by the project “Generalized Farkas lemma for a family of adjustable systems with uncertainty and applications”, Vietnam National University-Ho Chi Minh city, Vietnam. The research of the second author has been supported by Grant PID2022-136399NB-C21, funded by MICIU/AEI/10.13039/501100011033 and by ERDF/EU
Cs. Nagy Lajos : Helyesírási gyakorlókönyv : Budapest, Magyar Eszperantó Szövetség, 1989
No full textFarkas-type theorems for positively homogeneous semi-infinite systems
No full textThis article deals with systems of infinitely many inequalities involving functions that are positively homogeneous over a nonempty convex cone of the Euclidean space. Generalized convex conjugation theory is applied to derive a Farkas-type and a Gale-type theorem for this kind of systems. These results are particularized for linear and min-type inequality systems.The research of the first author has been partially supported by the Spanish Ministry of Science and Technology, project BFM2002-04114-C02, and by the sabbatical program of Alicante University. The work of the second author has been supported by the Spanish Ministry of Science and Technology, project BEC2002-00642, and by the Departament d’Universitats, Recerca i Societat de la Informació, Direcció General de Recerca de la Generalitat de Catalunya, project 2001SGR-00162. He also thanks the support of the Barcelona Economics Program of CREA
Knowledge-intensive business services: a brief overview
No full textIn the last decade of the 20th century knowledge has gained importance in the economy. This lead to the emergence of knowledge-based activities: knowledge-intensive organizations, and particularly knowledge-intensive services. These organizations function as external knowledge sources for other organizations. Their performance depends largely on professional knowledge. Since their performance has an impact on the success of their clients, it is important to look at those factors which influence the knowledge transfer between service provider and client organization. Based on theory and empirical research, the paper addresses the specific aspects of knowledge transfer from knowledge-intensive business service organizations to client organizations.Knowledge-intensive business services (KIBS), client organization, client knowledge., Research and Development/Tech Change/Emerging Technologies, L84,
Foliicolous lichen collections on Mount Kanga, Tanzania (East Africa)
No full textAbstract
The Tanzanian Mt Kanga was at first visited by Tamás Pócs in 1987 when he collected foliicolous lichens in lowland rainforest between 800 and 900 m elevation and in submontane rainforest between 900 and 1,250 m. Later, in 1989 he returned there with participants of the Nguru Mts expedition, when the author collected further lichens including foliicolous ones in three different forest types (dry evergreen and semi-evergreen forest at 600–800 m, submontane rainforest at 850–1,200 m and rocky forest at 1,200–1,300 m). Altogether 37 species became known from the area. The comparison of collections revealed that submontane rainforests (including rocky forests) are the richest of the studied forest types in foliicolous lichens. Mt Kanga is characterised by rare species like Calopadia editae discovered by Antonín Vězda in material from Mt Kanga, described and validated in 2011 by Chaves and Lücking based on materials from Mt Kanga and Costa Rica. The new combination Brasilicia dimerelloides (Vězda) Farkas is introduced. The palaeotropical Fouragea viridistellata (Sérus., Lücking et Sparrius) Ertz et Frisch described in 2008 is reported here as new for Tanzania
Stability conditions for the non-linear McKendrick equations
No full textNon-linear McKendrick equation with age-dependent mortality and fertility is considered. The author [Appl. Math. Comput. 131 (1) (2002) 107] deduced the characteristic equation whose roots determine the stability. We are able to give sufficient conditions for the stability of the stationary solutions of the system in some cases
SENIOR EMPLOYEES ON THE JOB MARKET OF EUROPEAN UNION
No full textIn the European countries life expectancy is growing, but people tend to retire earlier and earlier. The aim of our paper is to examine what measures the individual European countries take in order to keep senior citizens on their respective job markets as long as possible. Our essay consists of three parts. In the first part we examine the reform of the pension system. In the second part we survey the changing in-company employment policies. In the third part we examine the attempt of improvement of the employability of senior citizens themselves. The final conclusion of our paper can be summarised as follows: senior employees in general represent a significant group in human resources, the potentials of which ought to be and need to be utilized. Employers need to understand that the employment of senior people has its advantages. It is also very important to act accordingly.labour market, pension system, senior employees, human resource management
New Quercus-feeding Brevulacus species, redescription of Rhyncaphytoptus cerrifoliae Farkas and new Eriophyoid mite records from Hungary (Acari: Prostigmata: Eriophyoidea)
No full textAuthor made regular mite collectings between 1990 and 2010 on ornamental trees and shrubs, on streets, parks, in city greenery, forests, botanical gardens and private gardens, in various localities of Hungary. During this survey a new Quercus-infesting eriophyoid mite species was collected: Brevulacus carpathicus n. sp. is described and illustrated from Quercus petraea. Rhyncaphytoptus cerrifoliae Farkas is redescribed from Quercus cerris. Both species produce wax and are vagrant on the leaf undersurface. Two other species, viz. Aceria cichorii Petanović, Boczek et Shi and Cecidophyes tristernalis (Nalepa) are new species for the fauna of Hungary. Some faunistic data on the known taxa from this country are included
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